{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-1527","assignerOrgId":"ce714d77-add3-4f53-aff5-83d477b104bb","state":"PUBLISHED","assignerShortName":"openjs","dateReserved":"2026-01-28T12:05:08.491Z","datePublished":"2026-03-12T20:17:18.984Z","dateUpdated":"2026-03-13T18:06:03.794Z"},"containers":{"cna":{"providerMetadata":{"orgId":"ce714d77-add3-4f53-aff5-83d477b104bb","shortName":"openjs","dateUpdated":"2026-03-12T20:17:18.984Z"},"title":"undici is vulnerable to CRLF Injection via upgrade option","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-93","description":"CWE-93 Improper neutralization of CRLF sequences ('CRLF injection')","type":"CWE"}]}],"affected":[{"vendor":"undici","product":"undici","collectionURL":"https://github.com/nodejs/undici/","packageName":"undici","repo":"https://github.com/nodejs/undici/","versions":[{"status":"affected","version":"< 6.24.0; 7.0.0 < 7.24.0"},{"status":"unaffected","version":"6.24.0: 7.24.0"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\\r\\n) to:\n\n * Inject arbitrary HTTP headers\n * Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch)\nThe vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters:\n\n// lib/dispatcher/client-h1.js:1121\nif (upgrade) {\n header += `connection: upgrade\\r\\nupgrade: ${upgrade}\\r\\n`\n}","supportingMedia":[{"type":"text/html","base64":false,"value":"

Impact

When an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\\r\\n) to:

  1. Inject arbitrary HTTP headers
  2. Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch)

The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters:

// lib/dispatcher/client-h1.js:1121\nif (upgrade) {\n  header += `connection: upgrade\\r\\nupgrade: ${upgrade}\\r\\n`\n}
"}]}],"references":[{"url":"https://github.com/nodejs/undici/security/advisories/GHSA-4992-7rv2-5pvq"},{"url":"https://hackerone.com/reports/3487198"},{"url":"https://cna.openjsf.org/security-advisories.html"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","baseSeverity":"MEDIUM","baseScore":4.6,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N"}}],"credits":[{"lang":"en","value":"Matteo Collina","type":"remediation developer"},{"lang":"en","value":"Ulises Gascón","type":"remediation developer"},{"lang":"en","value":"Raul Vega del Valle","type":"analyst"}],"source":{"advisory":"GHSA-4992-7rv2-5pvq","discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-13T18:05:24.550959Z","id":"CVE-2026-1527","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-03-13T18:06:03.794Z"}}]}}