CVE-2026-45372 Details
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.
A vulnerability in cpp-httplib versions prior to 0.44.0 allows for CRLF injection through improper percent-decoding of HTTP header values. The library's server applies percent-decoding to most header values except for 'Location' and 'Referer'. This flaw enables encoded carriage return and line feed characters to be injected into headers, creating several potential attack vectors, such as HTTP response splitting and request smuggling.
Users are advised to update to cpp-httplib version 0.44.0 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 1, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m | CISA-ADP | ExploitMitigationVendor Advisory |
| https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-444 | Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') | [email protected] |
| CWE-93 | Improper Neutralization of CRLF Sequences ('CRLF Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| yhirose cpp-httplib | < 0.44.0 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 22, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 1, 2026 | CVE Modified | CISA-ADP |
| Jun 1, 2026 | Initial Analysis | [email protected] |
| May 29, 2026 | New CVE Received | [email protected] |