{"id":"CVE-2026-45372","state":"PUBLISHED","title":"cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection","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.","publishedAt":"2026-05-29T19:21:12.313Z","updatedAt":"2026-06-01T17:57:44.116Z","severity":{"score":9.9,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["yhirose cpp-httplib"],"affected":[{"vendor":"yhirose","product":"cpp-httplib","versions":[{"version":"< 0.44.0","status":"affected"}]}],"references":["https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m"],"weaknesses":["CWE-93","CWE-444"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45372.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45372","state":"PUBLISHED","datePublished":"2026-05-29T19:21:12.313Z","dateUpdated":"2026-06-01T17:57:44.116Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-12T00:51:29.086Z"},"containers":{"cna":{"title":"cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"yhirose","product":"cpp-httplib","versions":[{"version":"< 0.44.0","status":"affected"}]}],"references":[{"url":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m","name":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":9.9,"baseSeverity":"CRITICAL","confidentialityImpact":"LOW","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-93","lang":"en","description":"CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-444","lang":"en","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-29T19:21:12.313Z"},"source":{"advisory":"GHSA-xjxg-64p4-vj4m","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-01T17:57:24.969798Z","id":"CVE-2026-45372","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-01T17:57:44.116Z"}}]}}}