CVE-2026-46527

NameCVE-2026-46527
Descriptioncpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, When the server has called Server::set_trusted_proxies() with a non-empty trusted-proxy list, an attacker can send an HTTP request that includes an X-Forwarded-For header whose value parses to no valid IP segments. The code path then executes get_client_ip(), which calls front() on an empty std::vector—undefined behavior in C++. On typical implementations this manifests as abnormal process termination (denial of service). With Sanitizers enabled, you get an explicit runtime diagnostic. This vulnerability is fixed in 0.44.0.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1138578

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
cpp-httplib (PTS)bookworm0.11.4+ds-1+deb12u1vulnerable
trixie (security), trixie0.18.7-1+deb13u1vulnerable
forky, sid0.41.0+ds-3vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
cpp-httplibsource(unstable)(unfixed)1138578

Notes

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g

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