Contextualize Prioritize and ACT ON RISK
Login
Get Access
Demo

blog

Understanding and fixing Curl and libcurl Vulnerabilities CVE-2023-38545 and CVE-2023-38546 a detailed analysis

CVE-2023-38546, CVE-2023-38545 curl in the wild, libcurl, curl, vulnerability, application security, vulnerability management
CVE-2023-38546, curl in the wild, libcurl, curl, vulnerability, application security, vulnerability management

What is curl, and which version is vulnerable

Curl, a robust command-line tool used for transferring data with URLs, is an indispensable asset for developers and cybersecurity professionals. Its versatility in supporting various protocols makes it a go-to tool for many. However, like a fortified castle with a hidden weak spot, libcurl and the software itself too has its vulnerabilities. Recently, two notable Common Vulnerabilities and Exposures (CVEs) were identified – CVE-2023-38545 and CVE-2023-38546. The latter, rated as high severity, affects both libcurl and the curl tool, marking a significant security concern. This blog aims to delve into these vulnerabilities and provide a guide on how to ensure your software version or library like libcurl is updated and secure. Please follow the step below and the verification to ensure your vulnerability management program and applications in your application security program are secure.

Understanding CVE-2023-38545

Curl is used by security and developers alike, even a robust tool like Curl and libcurl isn’t impervious to vulnerabilities. One such vulnerability, CVE-2023-38545, has been tagged with a high-severity rating, affecting both libcurl and the curl tool. Its disclosure marked a significant moment, stirring discussions in the cybersecurity community. A GitHub discussion led by one of the software maintainer unveiled the upcoming release of the software version 8.4.0 on October 11, aimed at patching this security flaw alongside a low-severity vulnerability, CVE-2023-38546. Although details regarding the affected version range were withheld for security reasons, the announcement serves as a call to action for users to update their Curl version promptly.

In a recent twitter conversation, the curl team has warned teams for the October 11 release but without disclosing additional information on which version is likely to be vulnerable. This to discourage early attacks

<blockquote class=”twitter-tweet”><p lang=”en” dir=”ltr”>We are cutting the release cycle short and will release curl 8.4.0 on October 11, including a fix for a severity HIGH CVE. Buckle up.</p>&mdash; daniel:// stenberg:// (@bagder) <a href=”https://twitter.com/bagder/status/1709103920914526525?ref_src=twsrc%5Etfw”>October 3, 2023</a></blockquote> <script async src=”https://platform.twitter.com/widgets.js” charset=”utf-8″></script>

CVE-2023-38545 curl in the wild, libcurl, curl,

Recently curl was in the spotlight due to the erroneous disclosure:  maintainers have been vocal about downplaying the risk associated with most vulnerabilities reported against curl  in the past (a recent example is the article CVE-2020-19909 is everything that is wrong with CVEs), nonetheless in this case he warned — adding, “buckle up.”

Detail of the curl vulnerability vulnerability CVE-2023-38545 and CVE-2023-38546

libcurl, vulnerability, application security, vulnerability management

Update – Libcurl and chatgpt / LLM /BARD generated responses

The curl and other open source maintainers have been folded with requests through HackerOne and similar bug bounty platforms with bogus vulnerability reports. Be aware of wrong NVD information coming.

On the other hand NVD and curl library has a history of wrongly scored vulnerabilities like CVE-2022-42915 for more historical details refer to the Daniel Stenberg (one of the mantainer of curl) blog

How to upgrade to the Latest Stable Version: Curl 8.3.0 and new curl 8.4.0

As of now, the most recent stable release of software 8.3.0, which was unveiled on 2023-09-13. A significant number of downloads, precisely 88, are of this latest version, indicating a good rate of adoption within the user community. For those interested in exploring the code, the latest source code is accessible on GitHub, offering a glimpse into the engine room of this indispensable tool.

When is the next version of curl coming out?

The new release is scheduled for October the 11

Verifying Your Curl Version if is vulnerable to CVE-2023-38545 and CVE-2023-38546

Before diving into the update process, it’s crucial to ascertain the version of Curl you’re currently running. Here’s how:

  • Open your terminal.
  • Type in the command curl –version and hit enter.
  • The displayed output will indicate your Curl version.

Being cognizant of your software version is the first step towards ensuring a secure data transfer environment. If your version is prior to 8.4.0, consider updating to shield against the disclosed vulnerabilities.

macOS

  • Install Homebrew if you haven’t already, by running:
  • /bin/bash -c “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)”
  • Install the latest Curl version using Homebrew:
  • brew install curl
  • Update your PATH to prioritize the Homebrew version of Curl:
  • echo ‘export PATH=”/usr/local/opt/curl/bin:$PATH”‘ >> ~/.bash_profile
  • Source your updated ~/.bash_profile:
  • . ~/.bash_profile
  • Verify the update by checking the Curl version:

curl –version

Windows: 

  • Download the latest version from the official website and replace the old binaries.

Ubuntu/Debian:

  • sudoapt-get update && sudo apt-get install curl

Fedora:

  • sudo dnf upgrade cur

CentOS/RedHat:

  • sudo yum update curl

Each operating system has its own set of commands and procedures to update software. Ensure to backup any essential data and understand the update process to avoid any potential issues.

What is the exploitation data behind CVE-2023-38545 and CVE-2023-38546 In the wild

CVSS: TBD (assumed Critical)

CTI interest: Unknown

RCE Type Remote: Unknown (potential local authentication)

Availability: No

Status: Undisclosed

EPSS Score: – not registered –

Currently, there are 2673 systems with some version of curl exposed, but considering curl is embedded in every window, mac, linux version and container used like Amazon the spread and surface could be quite vaste

CVE-2023-38546, CVE-2023-38545 curl in the wild
CVE-2023-38546, CVE-2023-38545 curl in the wild, libcurl, curl, vulnerability, application security, vulnerability management

How Phoenix Can Help

To manage and prevent such vulnerabilities, comprehensive security solutions are essential. Phoenix Security offers tools such as Vulnerability Management and Asset Management to help organisations quickly act on vulnerabilities like OpenSSH’s CVE-2023-38408.

Phoenix Security serves as a beacon for security professionals aiming to pinpoint the Curl vulnerability within their systems. It meticulously scans through your product, identifying instances where the libcurl vulnerability may be installed or nested within libraries. By leveraging Phoenix Security, you not only unravel the potential threats but also take a significant stride in vulnerability management, ensuring your application security remains unassailable against the Curl vulnerability.

The Asset Management tool, on the other hand, provides a comprehensive view of all assets in an organization’s network. This can help organizations understand which assets are vulnerable to CVE-2023-38408 and need immediate patching.

Conclusion

The discovery of the OpenSSH’s Agent Forwarding CVE-2023-38408 vulnerability underscores the continuous need for rigorous security measures and immediate response. Even robust systems like OpenSSH can harbor hidden vulnerabilities. Proactively rectifying such vulnerabilities through actions such as implementing patches and using comprehensive security solutions like those offered by Phoenix Security is critical to maintaining the integrity of digital assets.

Get in control of your Application Security posture and Vulnerability management

Get a Demo today

Previous Issues of Vulnerability Weekly

Picture of Francesco Cipollone

Francesco Cipollone

Francesco is an internationally renowned public speaker, with multiple interviews in high-profile publications (eg. Forbes), and an author of numerous books and articles, who utilises his platform to evangelize the importance of Cloud security and cutting-edge technologies on a global scale.
7th October 2023
Francesco is an internationally renowned public speaker, with multiple interviews in high-profile publications (eg. Forbes), and an author of numerous books and articles, who utilises his platform to evangelize the importance of Cloud security and cutting-edge technologies on a global scale.

Discuss this blog with our community on Slack

Join our AppSec Phoenix community on Slack to discuss this blog and other news with our professional security team

Join Slack community
Linkedin-in Youtube Facebook-f Twitter Instagram

From our Blog

ASPM, rthreat centric, threat actor, agentic ai, aspm, application security, vulnerability managment.
  • 11th May 2025

The New role of Threat-Centric Approach in Application Security Posture Management (ASPM) an Agentic ASPM in real life

As cyber threats become increasingly sophisticated, the need for a more proactive and comprehensive approach to vulnerability management is undeniable. A threat-centric methodology, when combined with advanced tools like Agentic AI and Application Security Posture Management (ASPM), offers organizations the ability to predict and mitigate vulnerabilities before they are exploited by threat actors. This article delves into how leveraging threat intelligence, exposure and reachability analysis, and contextual risk assessments can help organizations stay ahead of cyber threats, specifically focusing on high-risk vulnerabilities like remote code execution (RCE) and memory corruption. Through case studies like Citrix ADC and MOVEit Transfer, the article highlights the growing trend of zero-day exploits and emphasizes the importance of a proactive, data-driven security strategy. In a world where vulnerabilities are constantly targeted, adopting a threat-centric approach is not just a best practice—it’s essential to ensuring long-term security. For startups, the focus is clear—establish visibility and ensure core security practices are in place. Application Security Posture Management (ASPM) tools provide a straightforward, automated approach to detecting vulnerabilities and enforcing policies. These solutions help reduce risk quickly without overburdening small security teams. Mature organizations, on the other hand, are tackling a different set of problems. With the sheer number of vulnerabilities and an increasingly complicated threat landscape, enterprises need to fine-tune their approach. The goal shifts toward intelligent remediation, leveraging real-time threat intelligence and advanced risk prioritization. ASPM tools at this stage do more than just detect vulnerabilities—they provide context, enable proactive decision-making, and streamline the entire remediation process. The emergence of AI-assisted code generation has further complicated security in both environments. These tools, while speeding up development, are often responsible for introducing new vulnerabilities into applications at a faster pace than traditional methods. The challenge is clear: AI-generated code can hide flaws that are difficult to catch in the rush of innovation. Both startups and enterprises need to adjust their security posture to account for these new risks. ASPM platforms, like Phoenix Security, provide automated scanning of code before it hits production, ensuring that flaws don’t make it past the first line of defense. Meanwhile, organizations are also grappling with the backlog crisis in the National Vulnerability Database (NVD). A staggering number of CVEs remain unprocessed, leaving many businesses with limited data on which to base their patching decisions. While these delays leave companies vulnerable, Phoenix Security steps in by cross-referencing CVE data with known exploits and live threat intelligence, helping organizations stay ahead despite the lag in official vulnerability reporting. Whether just starting their security program or managing a complex infrastructure, organizations need a toolset that adapts with them. Phoenix Security enables businesses of any size to prioritize vulnerabilities based on actual risk, not just theoretical impact, helping security teams navigate the evolving threat landscape with speed and accuracy.
Francesco Cipollone
  • 27th April 2025

ASPM at Two Speeds: Remediation Strategies for Every Security Journey & CVE/NVD Collapse

The journey of securing an organization’s application landscape varies dramatically, depending on where a company stands in its maturity. Early-stage startups with small security teams face challenges not only with vulnerabilities but also with scaling their security processes in line with their growth. On the flip side, established enterprises struggle with managing complex environments, prioritizing remediation, and dealing with vast amounts of vulnerabilities while staying ahead of sophisticated threats. For startups, the focus is clear—establish visibility and ensure core security practices are in place. Application Security Posture Management (ASPM) tools provide a straightforward, automated approach to detecting vulnerabilities and enforcing policies. These solutions help reduce risk quickly without overburdening small security teams. Mature organizations, on the other hand, are tackling a different set of problems. With the sheer number of vulnerabilities and an increasingly complicated threat landscape, enterprises need to fine-tune their approach. The goal shifts toward intelligent remediation, leveraging real-time threat intelligence and advanced risk prioritization. ASPM tools at this stage do more than just detect vulnerabilities—they provide context, enable proactive decision-making, and streamline the entire remediation process. The emergence of AI-assisted code generation has further complicated security in both environments. These tools, while speeding up development, are often responsible for introducing new vulnerabilities into applications at a faster pace than traditional methods. The challenge is clear: AI-generated code can hide flaws that are difficult to catch in the rush of innovation. Both startups and enterprises need to adjust their security posture to account for these new risks. ASPM platforms, like Phoenix Security, provide automated scanning of code before it hits production, ensuring that flaws don’t make it past the first line of defense. Meanwhile, organizations are also grappling with the backlog crisis in the National Vulnerability Database (NVD). A staggering number of CVEs remain unprocessed, leaving many businesses with limited data on which to base their patching decisions. While these delays leave companies vulnerable, Phoenix Security steps in by cross-referencing CVE data with known exploits and live threat intelligence, helping organizations stay ahead despite the lag in official vulnerability reporting. Whether just starting their security program or managing a complex infrastructure, organizations need a toolset that adapts with them. Phoenix Security enables businesses of any size to prioritize vulnerabilities based on actual risk, not just theoretical impact, helping security teams navigate the evolving threat landscape with speed and accuracy.
Francesco Cipollone
NVD, Mitre, Failure
  • 16th April 2025

The CVE & NVD Crisis: A Wake-Up Call for Cybersecurity Industry andApplication Security

The cybersecurity world is reeling as MITRE’s funding for the CVE and NVD systems expires, disrupting the backbone of global vulnerability management. As traditional sources like the National Vulnerability Database collapse under funding cuts and submission backlogs, security teams face delays, incomplete data, and loss of automation in remediation pipelines. This isn’t just a data problem—it’s a structural crisis for application security and vulnerability correlation. In this landscape of uncertainty, Phoenix Security’s ASPM platform steps up with a code-to-cloud correlation engine that doesn’t depend on outdated data workflows. By connecting code-level insights (including tools like Semgrep) to runtime and cloud environments, Phoenix enables faster, context-aware vulnerability remediation—even as NVD and CVE pipelines deteriorate. This article dives into the implications of the CVE shutdown and how Phoenix Security is helping security and development teams transition to a resilient, correlation-first approach to cybersecurity.
Francesco Cipollone
  • 8th April 2025

Announcing Phoenix Threat Centric Approach

Learn how to predict ransomware risks and vulnerability exploitation using a threat-centric approach. Explore data-driven insights, verified exploit trends, and methods for assessing the likelihood of attacks with key references to CISA KEV, EPSS, and Phoenix Security’s 4D Risk Formula.
Francesco Cipollone
  • 8th April 2025

A Threat-Centric Look at Vulnerability Exploitation Likelihood and Ransomware Risk

Remote Code Execution flaws continue to undermine Kubernetes ingress integrity. IngressNightmare (CVE-2025-1097, CVE-2025-1098, CVE-2025-24514, CVE-2025-1974) showcases severe threat vectors in NGINX-based proxies, leading to cluster-wide exposure. ASPM, robust remediation tactics, and strong application security solutions—like Phoenix Security—mitigate these vulnerabilities before ransomware groups exploit them.
Francesco Cipollone
  • 25th March 2025

IS  NGINX IngressNightmare bad? Bad news it is: Critical Remote Code Execution Threats (CVE-2025-1097, CVE-2025-1098, CVE-2025-24514, CVE-2025-1974)

Remote Code Execution flaws continue to undermine Kubernetes ingress integrity. IngressNightmare (CVE-2025-1097, CVE-2025-1098, CVE-2025-24514, CVE-2025-1974) showcases severe threat vectors in NGINX-based proxies, leading to cluster-wide exposure. ASPM, robust remediation tactics, and strong application security solutions—like Phoenix Security—mitigate these vulnerabilities before ransomware groups exploit them.
Francesco Cipollone
Derek

Derek Fisher

Linkedin

Head of product security at a global fintech

Derek Fisher – Head of product security at a global fintech. Speaker, instructor, and author in application security.

Derek is an award winning author of a children’s book series in cybersecurity as well as the author of “The Application Security Handbook.” He is a university instructor at Temple University where he teaches software development security to undergraduate and graduate students. He is a speaker on topics in the cybersecurity space and has led teams, large and small, at organizations in the healthcare and financial industries. He has built and matured information security teams as well as implemented organizational information security strategies to reduce the organizations risk.

Derek got his start in the hardware engineering space where he learned about designing circuits and building assemblies for commercial and military applications. He later pursued a computer science degree in order to advance a career in software development. This is where Derek was introduced to cybersecurity and soon caught the bug. He found a mentor to help him grow in cybersecurity and then pursued a graduate degree in the subject.

Since then Derek has worked in the product security space as an architect and leader. He has led teams to deliver more secure software in organizations from multiple industries. His focus has been to raise the security awareness of the engineering organization while maintaining a practice of secure code development, delivery, and operations.

In his role, Jeevan handles a range of tasks, from architecting security solutions to collaborating with Engineering Leadership to address security vulnerabilities at scale and embed security into the fabric of the organization.

Jeevan Singh

Jeevan Singh

Linkedin

Founder of Manicode Security

Jeevan Singh is the Director of Security Engineering at Rippling, with a background spanning various Engineering and Security leadership roles over the course of his career. He’s dedicated to the integration of security practices into software development, working to create a security-aware culture within organizations and imparting security best practices to the team.
In his role, Jeevan handles a range of tasks, from architecting security solutions to collaborating with Engineering Leadership to address security vulnerabilities at scale and embed security into the fabric of the organization.

James

James Berthoty

Linkedin

Founder of Latio Tech

James Berthoty has over ten years of experience across product and security domains. He founded Latio Tech to help companies find the right security tools for their needs without vendor bias.

christophe

Christophe Parisel

Linkedin

Senior Cloud Security Architect

Senior Cloud Security Architect

Chris

Chris Romeo

Linkedin

Co-Founder
Security Journey

Chris Romeo is a leading voice and thinker in application security, threat modeling, and security champions and the CEO of Devici and General Partner at Kerr Ventures. Chris hosts the award-winning “Application Security Podcast,” “The Security Table,” and “The Threat Modeling Podcast” and is a highly rated industry speaker and trainer, featured at the RSA Conference, the AppSec Village @ DefCon, OWASP Global AppSec, ISC2 Security Congress, InfoSec World and All Day DevOps. Chris founded Security Journey, a security education company, leading to an exit in 2022. Chris was the Chief Security Advocate at Cisco, spreading security knowledge through education and champion programs. Chris has twenty-six years of security experience, holding positions across the gamut, including application security, security engineering, incident response, and various Executive roles. Chris holds the CISSP and CSSLP certifications.

jim

Jim Manico

Linkedin

Founder of Manicode Security

Jim Manico is the founder of Manicode Security, where he trains software developers on secure coding and security engineering. Jim is also the founder of Brakeman Security, Inc. and an investor/advisor for Signal Sciences. He is the author of Iron-Clad Java: Building Secure Web Applications (McGraw-Hill), a frequent speaker on secure software practices, and a member of the JavaOne Rockstar speaker community. Jim is also a volunteer for and former board member of the OWASP foundation.

Join our Mailing list!

Get all the latest news, exclusive deals, and feature updates.

The IKIGAI concept
x Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
ShieldPRO →