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CVE-2026-6331

CVE-2026-6331 · HMAC zero-length tag forgery in EVP_DigestVerifyFinal

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

HMAC zero-length tag forgery in EVP_DigestVerifyFinal, where a zero-length tag could be accepted as valid during HMAC verification. In the OpenSSL-compatibility HMAC verify path the supplied signature length was only checked as not exceeding the MAC length, so a zero-length or otherwise truncated tag could pass verification. The fix requires the supplied tag length to exactly equal the MAC length and rejects a zero-length MAC, so a forged short or empty tag is no longer accepted.

CVSS 2.1 · Low · EPSS 0.2% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • wolfssl

    Versions
    • ≥ 3.15.5, ≤ 5.9.1: Affected (semver)

    No fix published

  • wolfssl Debian:12

    Versions
    • 5.5.4-2
    • 5.5.4-2+deb12u1
    • 5.5.4-2+deb12u2
    Affected ranges
    • ECOSYSTEM: < 5.5.4-2+deb12u3

    Update to 5.5.4-2+deb12u3

  • wolfssl Debian:13

    Versions
    • 5.7.2-0.1
    • 5.7.2-0.1+deb13u1
    Affected ranges
    • ECOSYSTEM: < 5.7.2-0.1+deb13u2

    Update to 5.7.2-0.1+deb13u2

  • wolfssl Ubuntu:16.04:LTS

    Versions
    • 3.4.8+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wolfssl Ubuntu:18.04:LTS

    Versions
    • 3.10.2+dfsg-2
    • 3.12.0+dfsg-1
    • 3.12.2+dfsg-1
    • 3.13.0+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wolfssl Ubuntu:20.04:LTS

    Versions
    • 4.1.0+dfsg-2
    • 4.2.0+dfsg-1
    • 4.2.0+dfsg-2
    • 4.2.0+dfsg-3
    • 4.3.0+dfsg-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wolfssl Ubuntu:22.04:LTS

    Versions
    • 4.6.0-3
    • 5.0.0-1
    • 5.1.1-1
    • 5.2.0-1
    • 5.2.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wolfssl Ubuntu:24.04:LTS

    Versions
    • 5.5.4-2
    • 5.5.4-2.1
    • 5.6.4-2
    • 5.6.6-1.2
    • 5.6.6-1.3
    • 5.6.6-1.3build1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wolfssl Ubuntu:25.10

    Versions
    • 5.7.2-0.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wolfssl Ubuntu:26.10

    Versions
    • 5.9.1-0.1
    • 5.9.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wolfssl Ubuntu:26.04:LTS

    Versions
    • 5.7.2-0.1
    • 5.8.2-1.2
    • 5.8.4-1
    • 5.9.1-0.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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