{"id":"CVE-2026-15603","summary":"morgan vulnerable to Log Forging via unescaped Unicode line separators","details":"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.","aliases":["GHSA-jxfw-x594-9x9m"],"modified":"2026-09-03T03:47:48.634427106Z","published":"2026-08-28T13:41:49.521Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/15xxx/CVE-2026-15603.json","cna_assigner":"openjs","cwe_ids":["CWE-117"]},"references":[{"type":"ADVISORY","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/15xxx/CVE-2026-15603.json"},{"type":"ADVISORY","url":"https://github.com/expressjs/morgan/security/advisories/GHSA-jxfw-x594-9x9m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-15603"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/expressjs/morgan","events":[{"introduced":"0"},{"fixed":"063f084a8de1fe02e52333f0b5df2533ced85e42"}],"database_specific":{"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:morgan_project:morgan:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"0"},{"fixed":"1.12.0"}]}}],"versions":["1.11.0","1.10.0","1.9.1","1.9.0","1.8.2","1.8.1","1.8.0","1.7.0","1.6.1","1.6.0","1.5.3","1.5.2","1.5.1","1.5.0","1.4.1","1.4.0","1.3.2","1.3.1","1.3.0","1.2.3","1.2.2","1.2.1","1.2.0","1.1.1","1.1.0","1.0.1","1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-15603.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}