Critical
cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-45372
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 06:07 UTC · Revision 1
Source evidence
cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection
core-osv · Original sourcePublished 29 May 2026, 19:21 UTC
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.
osv:CVE-2026-45372
Complete source record
{
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"url": "https://osv.dev/vulnerability/CVE-2026-45372",
"method": "structured",
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"title": "cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection",
"summary": "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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"modified": "2026-10-28T02:30:26.389607737Z",
"provider": "osv",
"references": [
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"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m",
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"source_id": "core-osv",
"document_id": 492929,
"published_at": "2026-05-29T19:21:12.313+00:00"
}