Bug 2445491 (CVE-2026-29076)

Summary: CVE-2026-29076 cpp-httplib: cpp-httplib: Denial of Service via crafted HTTP POST request
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in cpp-httplib, a C++11 single-file header-only cross-platform HTTP/HTTPS library. A remote attacker can exploit this vulnerability by sending a specially crafted HTTP POST request with a malicious filename* parameter in the Content-Disposition header. This triggers uncontrolled stack growth due to the std::regex engine's deep recursion, leading to a stack overflow and causing the server process to crash, resulting in a Denial of Service (DoS).
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Bug Depends On: 2445663, 2445664    
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Description OSIDB Bzimport 2026-03-07 17:01:28 UTC 
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.