{"cve":"CVE-2026-15603","nvd":{"published":"2026-08-28T16:17:07.417","modified":"2026-08-31T17:11:12.057","status":"Analyzed","description":"morgan is an HTTP request logger middleware for Node.js. In versions prior to 1.12.0, the internal helper that escapes log token values did not neutralize the Unicode line separator characters U+0085 (Next Line), U+2028 (Line Separator), and U+2029 (Paragraph Separator). An unauthenticated remote client can place these characters in an attacker-controlled log token, for example a Basic auth username surfaced through the remote-user token, so that Unicode-aware downstream log processing splits a single request log into multiple logical records. This is a log forging issue (CWE-117) and an incomplete-fix follow-up to CVE-2026-5078, which only addressed ASCII control characters. The issue is fixed in morgan 1.12.0, which extends the escaping set to cover these Unicode line separators. Upgrade to morgan 1.12.0 to remediate.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-117"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/expressjs/morgan/security/advisories/GHSA-jxfw-x594-9x9m"],"products":["morgan_project:morgan"],"source":"nvd","synced_at":"2026-10-19T22:50:50.842544443+00:00"},"epss":{"cve":"CVE-2026-15603","score":0.00397,"percentile":0.3396,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-jxfw-x594-9x9m","url":"https://osv.dev/vulnerability/GHSA-jxfw-x594-9x9m","summary":"morgan vulnerable to Log Forging via unescaped Unicode line separators","modified":"2026-09-08T21:45:04.626840405Z","packages":[{"ecosystem":"npm","name":"morgan","purl":"pkg:npm/morgan","ranges":["<1.12.0"],"fixed":["1.12.0"]}]}],"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."]}