High
cpp-httplib — security advisory
cpp-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.
- Products
- cpp-httplib
- Affected versions
- 0.10.1+ds-1, 0.10.2+ds-1, 0.10.3+ds-1, 0.10.3+ds-1ubuntu0.1~esm1, 0.10.3+ds-1ubuntu0.1~esm2, 0.13.1+ds-1ubuntu1, 0.14.3+ds-1, 0.14.3+ds-1.1, 0.14.3+ds-1.1build1, 0.14.3+ds-1.1build2, 0.14.3+ds-1.1ubuntu0.1~esm1, 0.14.3+ds-1.1ubuntu0.1~esm2, 0.18.7-1, 0.18.7-1ubuntu0.25.10.1, 0.18.7-1ubuntu0.25.10.2, 0.26.0+ds-2ubuntu2, 0.26.0+ds-2ubuntu3, 0.26.0+ds-2ubuntu3+esm1, 0.26.0+ds-2ubuntu4, 0.9.10+ds-1, 0.9.9+ds-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-46527
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:05 UTC · Revision 1
Source evidence
cpp-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.
osv:UBUNTU-CVE-2026-46527
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
Complete source record
{
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"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-46527",
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"title": "UBUNTU-CVE-2026-46527",
"summary": "cpp-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.",
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"modified": "2026-10-17T13:00:13.003573652Z",
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"published_at": "2026-05-29T20:16:00+00:00"
}