{"id":"CVE-2026-21428","state":"PUBLISHED","title":"cpp-httplib has CRLF injection in http headers","description":"cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the ``write_headers`` function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines.\nThis vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue.","publishedAt":"2026-01-01T17:54:43.959Z","updatedAt":"2026-01-02T18:50:20.380Z","severity":{"score":7.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P","source":"GitHub_M"},"assigner":"GitHub_M","products":["yhirose cpp-httplib"],"affected":[{"vendor":"yhirose","product":"cpp-httplib","versions":[{"version":"< 0.30.0","status":"affected"}]}],"references":["https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-wpc6-j37r-jcx7","https://github.com/yhirose/cpp-httplib/commit/98048a033a532ff22320ce1d11789f8d5710dfcd","https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.0"],"weaknesses":["CWE-93"],"ingestedAt":"2026-10-29T20:11:10.572Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/21xxx/CVE-2026-21428.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-21428","state":"PUBLISHED","datePublished":"2026-01-01T17:54:43.959Z","dateUpdated":"2026-01-02T18:50:20.380Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2025-12-29T03:00:29.274Z"},"containers":{"cna":{"title":"cpp-httplib has CRLF injection in http headers","descriptions":[{"lang":"en","value":"cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the ``write_headers`` function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines.\nThis vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue."}],"affected":[{"vendor":"yhirose","product":"cpp-httplib","versions":[{"version":"< 0.30.0","status":"affected"}]}],"references":[{"url":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-wpc6-j37r-jcx7","name":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-wpc6-j37r-jcx7","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/yhirose/cpp-httplib/commit/98048a033a532ff22320ce1d11789f8d5710dfcd","name":"https://github.com/yhirose/cpp-httplib/commit/98048a033a532ff22320ce1d11789f8d5710dfcd","tags":["x_refsource_MISC"]},{"url":"https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.0","name":"https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":7.7,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-93","lang":"en","description":"CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-01-01T17:54:43.959Z"},"source":{"advisory":"GHSA-wpc6-j37r-jcx7","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-01-02T18:50:07.704892Z","id":"CVE-2026-21428","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":"2026-01-02T18:50:20.380Z"}}]}}}