VDB
CVE-2026-45372
CVE-2026-45372
PUBLISHED
CVSS 9.9 CRITICAL
Reported by GitHub_M · Published May 29, 2026
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, when cpp-httplib's server parses an incoming request, it applies percent-decoding to every header value except Location and Referer. The validity check (is_field_value) is run before decoding, so encoded %0D%0A passes the check and is then expanded to a literal \r\n byte pair inside the stored header value. This vulnerability is fixed in 0.44.0.
Risk Scores
CVSS 3.1
9.9
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| yhirose | cpp-httplib | < 0.44.0 |
| yhirose | cpp-httplib | < 0.44.0, < 0.44.0 |
Timeline
- May 29, 2026 CVE Published
- May 30, 2026 EPSS Score
- May 31, 2026 EPSS Score
- Jun 1, 2026 EPSS Score
- Jun 1, 2026 Security Advisory
- Jun 5, 2026 EPSS Score
- Jun 6, 2026 Coalition ESS Score
- Aug 7, 2026 EPSS Score
- Aug 24, 2026 EPSS Score
- Aug 28, 2026 EPSS Score
- Sep 3, 2026 EPSS Score
- Sep 8, 2026 EPSS Score
References
- https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m x_refsource_CONFIRM