CVE-2026-45372

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.

CVSS v3 9.9 CRITICAL

9.9^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.3

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact HIGH

Availability Impact LOW

Scope CHANGED

References

Link	Resource
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m	Exploit Mitigation Vendor Advisory
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m	Exploit Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-05-29 20:16

Updated : 2026-07-22 06:10

NVD link : CVE-2026-45372

Mitre link : CVE-2026-45372

CVE.ORG link : CVE-2026-45372

JSON object : View

Products Affected

yhirose

cpp-httplib

CWE

CWE-93

Improper Neutralization of CRLF Sequences ('CRLF Injection')

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

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