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CVE-2026-15603

CVE-2026-15603 · morgan vulnerable to Log Forging via unescaped Unicode line separators

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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 5.3 · Medium · EPSS 0.4% · Fix available

Published
Updated

Stack: system · node

Affected products and versions

  • morgan

    Versions
    • ≥ 0, < 1.12.0: Affected (semver)

    Update to 1.12.0

  • node-morgan Debian:12

    Versions
    • 1.10.0+~1.9.3-1
    • 1.10.1+~1.9.10-1
    • 1.12.0+~1.9.10-1
    • 1.12.1+~1.9.10-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-morgan Debian:13

    Versions
    • 1.10.0+~1.9.3-1
    • 1.10.1+~1.9.10-1
    • 1.12.0+~1.9.10-1
    • 1.12.1+~1.9.10-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-morgan Debian:14

    Versions
    • 1.10.0+~1.9.3-1
    • 1.10.1+~1.9.10-1
    Affected ranges
    • ECOSYSTEM: < 1.12.0+~1.9.10-1

    Update to 1.12.0+~1.9.10-1

  • morgan npm

    Affected ranges
    • SEMVER: < 1.12.0

    Update to 1.12.0

  • node-morgan Ubuntu:22.04:LTS

    Versions
    • 1.10.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-morgan Ubuntu:24.04:LTS

    Versions
    • 1.10.0+~1.9.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-morgan Ubuntu:26.10

    Versions
    • 1.10.1+~1.9.10-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-morgan Ubuntu:26.04:LTS

    Versions
    • 1.10.0+~1.9.3-1
    • 1.10.1+~1.9.10-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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