{"cve":"CVE-2026-1527","nvd":{"published":"2026-03-12T21:16:25.137","modified":"2026-06-17T10:16:00.187","status":"Analyzed","description":"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}","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N","score":4.6},"cwes":["CWE-93"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/nodejs/undici/security/advisories/GHSA-4992-7rv2-5pvq","https://hackerone.com/reports/3487198"],"products":["nodejs:undici"],"source":"nvd","synced_at":"2026-10-19T22:25:53.701907451+00:00"},"epss":{"cve":"CVE-2026-1527","score":0.00287,"percentile":0.21318,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-4992-7rv2-5pvq","url":"https://osv.dev/vulnerability/GHSA-4992-7rv2-5pvq","summary":"Undici has CRLF Injection in undici via `upgrade` option","modified":"2026-09-10T03:50:37.246920699Z","packages":[{"ecosystem":"npm","name":"undici","purl":"pkg:npm/undici","ranges":["<6.24.0"],"fixed":["6.24.0"]},{"ecosystem":"npm","name":"undici","purl":"pkg:npm/undici","ranges":[">=7.0.0 <7.24.0"],"fixed":["7.24.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}