CVE-2026-29076

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.

Score

CVSS 3.1 5.9 Medium

Status

Analyzed - security-advisories@github.com

Published

2026-03-07

Last modified

2026-03-09

Weaknesses

CWE-1333, CWE-674

Affected products

• Cpp-httplib (Yhirose)

References

• https://github.com/yhirose/cpp-httplib/commit/de296af3eb5b0d5c116470e033db900e4812c5e6
• https://github.com/yhirose/cpp-httplib/releases/tag/v0.37.0
• https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-qq6v-r583-3h69