{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-5078", "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "state": "PUBLISHED", "assignerShortName": "openjs", "dateReserved": "2026-03-28T17:42:51.328Z", "datePublished": "2026-06-03T05:56:49.512Z", "dateUpdated": "2026-06-03T05:56:49.512Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "shortName": "openjs", "dateUpdated": "2026-06-03T05:56:49.512Z"}, "title": "morgan vulnerable to Log Forging via unneutralized control characters in :remote-user", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-117", "description": "CWE-117: Improper Output Neutralization for Logs", "type": "CWE"}]}], "affected": [{"vendor": "morgan", "product": "morgan", "versions": [{"status": "affected", "version": "1.2.0", "lessThanOrEqual": "1.10.1", "versionType": "semver"}, {"status": "unaffected", "version": "1.11.0", "versionType": "semver"}], "defaultStatus": "unaffected", "packageURL": "pkg:npm/morgan"}], "descriptions": [{"lang": "en", "value": "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.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "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."}]}], "references": [{"url": "https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m"}, {"url": "https://cna.openjsf.org/security-advisories.html"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE", "baseSeverity": "MEDIUM", "baseScore": 5.3, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}}], "credits": [{"lang": "en", "value": "Yuki Matsuhashi", "type": "reporter"}, {"lang": "en", "value": "Ulises Gasc\u00f3n", "type": "remediation developer"}, {"lang": "en", "value": "Jon Church", "type": "remediation developer"}], "x_generator": {"engine": "cve-kit 1.0.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "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", "lastModified": "2026-06-03T08:16:19.743", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "type": "Secondary"}]}, "published": "2026-06-03T08:16:19.743", "references": [{"source": "ce714d77-add3-4f53-aff5-83d477b104bb", "url": "https://cna.openjsf.org/security-advisories.html"}, {"source": "ce714d77-add3-4f53-aff5-83d477b104bb", "url": "https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m"}], "sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-117"}], "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "type": "Secondary"}]}

{}

{"created": "2026-06-03T12:30:26.158825+00:00", "updated": "2026-06-03T12:30:26.158837+00:00", "vendors": []}