CVE-2026-29076
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.
Does this matter?
Lower severity and a low EPSS score (0.64%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.64% probability · 50th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-674, CWE-1333
- Affected
- yhirose/cpp-httplib
- Source
- security-advisories@github.com
EPSS 0.6% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.