yhirose cpp-httplib up to 0.36.x Content-Disposition Parser std::regex recursion

Summaryinfo

A vulnerability, which was classified as problematic, has been found in yhirose cpp-httplib up to 0.36.x. This vulnerability affects the function std::regex of the component Content-Disposition Parser. This manipulation causes recursion. This vulnerability appears as CVE-2026-29076. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in yhirose cpp-httplib up to 0.36.x. It has been declared as problematic. Affected by this vulnerability is the function std::regex of the component Content-Disposition Parser. The manipulation with an unknown input leads to a recursion vulnerability. The CWE definition for the vulnerability is CWE-674. The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. As an impact it is known to affect availability. The summary by CVE is:

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.37.0, cpp-httplib uses std::regex (libstdc++) to parse RFC 5987 encoded filename* values in multipart Content-Disposition headers. The regex engine in libstdc++ implements backtracking via deep recursion, consuming one stack frame per input character. An attacker can send a single HTTP POST request with a crafted filename* parameter that causes uncontrolled stack growth, resulting in a stack overflow (SIGSEGV) that crashes the server process. This issue has been patched in version 0.37.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-29076 since 03/03/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 301478 (Linux Distros Unpatched Vulnerability : CVE-2026-29076), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.37.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch de296af3eb5b0d5c116470e033db900e4812c5e6 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (301478) and EUVD (EUVD-2026-10158). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• yhirose

Name

• cpp-httplib

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12
• 0.13
• 0.14
• 0.15
• 0.16
• 0.17
• 0.18
• 0.19
• 0.20
• 0.21
• 0.22
• 0.23
• 0.24
• 0.25
• 0.26
• 0.27
• 0.28
• 0.29
• 0.30
• 0.31
• 0.32
• 0.33
• 0.34
• 0.35
• 0.36

License

• open-source

Website

• Product: https://github.com/yhirose/cpp-httplib/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion