CVE-2026-45372

critical · 9.9

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.

9.9

CVSS

0.3%

EPSS (exploit prob.)

22nd

EPSS percentile

2026-05-29

Published

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L

Weaknesses

CWE-93CWE-444

Affected products

Vendor	Product	Affected versions
yhirose	cpp-httplib	< 0.44.0

Check a specific version with /api/v1/cve/match.

References

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-45372