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CVE-2026-49852

CVE-2026-49852 · joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)

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

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.

CVSS 8.7 · High · EPSS 0.2% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • joserfc

    Versions
    • < 1.6.8: Affected

    No fix published

  • joserfc Debian:13

    Versions
    • 1.1.0-1
    • 1.2.0-1
    • 1.2.2-1
    • 1.3.1-1
    • 1.3.2-1
    • 1.3.4-1
    • 1.4.0-1
    • 1.4.1-1
    • 1.4.3-1
    • 1.5.0-1
    • 1.6.0-1
    • 1.6.1-1
    • 1.6.2-1
    • 1.6.3-1
    • 1.6.4-1
    • 1.6.5-1
    • 1.6.8-1
    • 1.7.0-1
    • 1.7.1-1
    • 1.7.2-1
    • 1.7.3-1
    • 1.7.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • joserfc Debian:14

    Versions
    • 1.1.0-1
    • 1.2.0-1
    • 1.2.2-1
    • 1.3.1-1
    • 1.3.2-1
    • 1.3.4-1
    • 1.4.0-1
    • 1.4.1-1
    • 1.4.3-1
    • 1.5.0-1
    • 1.6.0-1
    • 1.6.1-1
    • 1.6.2-1
    • 1.6.3-1
    • 1.6.4-1
    • 1.6.5-1
    Affected ranges
    • ECOSYSTEM: < 1.6.8-1

    Update to 1.6.8-1

  • joserfc PyPI

    Versions
    • 0.1.0
    • 0.10.0
    • 0.11.0
    • 0.11.1
    • 0.12.0
    • 0.2.0
    • 0.3.0
    • 0.4.0
    • 0.5.0
    • 0.6.0
    • 0.7.0
    • 0.8.0
    • 0.9.0
    • 1.0.0
    • 1.0.1
    • 1.0.2
    • 1.0.3
    • 1.0.4
    • 1.1.0
    • 1.2.0
    • 1.2.1
    • 1.2.2
    • 1.3.0
    • 1.3.1
    • 1.3.2
    • 1.3.3
    • 1.3.4
    • 1.3.5
    • 1.4.0
    • 1.4.1
    • 1.4.2
    • 1.4.3
    • 1.5.0
    • 1.6.0
    • 1.6.1
    • 1.6.2
    • 1.6.3
    • 1.6.4
    • 1.6.5
    • 1.6.7
    Affected ranges
    • ECOSYSTEM: < 1.6.8

    Update to 1.6.8

  • joserfc Ubuntu:26.04:LTS

    Versions
    • 1.2.2-1
    • 1.4.0-1
    • 1.4.1-1
    • 1.4.3-1
    • 1.5.0-1
    • 1.6.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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