{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:morgan_project:morgan:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "1.2.0"
              },
              {
                "last_affected": "1.10.1"
              },
              {
                "fixed": "1.11.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_RANGE"
            ]
          },
          "events": [
            {
              "introduced": "34f0479eaf433191a264c1dce2b11c521f9749c0"
            },
            {
              "fixed": "e0e6f17574db56396f8e60ebb03bb7aaaeb9cc6f"
            }
          ],
          "repo": "https://github.com/expressjs/morgan",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-4vj7-5mj6-jm8m"
  ],
  "database_specific": {
    "cna_assigner": "openjs",
    "cwe_ids": [
      "CWE-117"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5078.json"
  },
  "details": "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.",
  "id": "CVE-2026-5078",
  "modified": "2026-07-16T03:31:10.828965091Z",
  "published": "2026-06-03T05:56:49.512Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5078.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5078"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "morgan vulnerable to Log Forging via unneutralized control characters in :remote-user"
}