CVE-2026-45372

9.9 CRITICAL
Published: May 29, 2026 Modified: June 01, 2026
View on NVD

Description

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m
Source: security-advisories@github.com
Exploit Mitigation Vendor Advisory
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Mitigation Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.9 / 10.0
EPSS (Exploit Probability)
0.1%
18th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

yhirose