{"id":"CVE-2026-5078","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-5078","generatedAt":"2026-10-28T03:24:57.928Z","title":"Impact: The morgan logging middleware's :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters.","description":"Impact: The morgan logging middleware's :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user.","published":"2026-06-03T08:16:20.000Z","lastModified":"2026-07-22T19:10:00.000Z","status":"Analyzed","sourceIdentifier":"ce714d77-add3-4f53-aff5-83d477b104bb","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"cwe":["CWE-117"],"affected":["morgan project/morgan"],"epss":{"score":0.00332,"percentile":0.26208,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.33%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://cna.openjsf.org/security-advisories.html","tags":["Third Party Advisory"],"source":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m","tags":["Mitigation","Vendor Advisory"],"source":"ce714d77-add3-4f53-aff5-83d477b104bb"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-5078","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}