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CVE-2026-27932

CVE-2026-27932 · joserfc PBES2 p2c Unbounded Iteration Count enables Denial of Service (DoS)

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. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (DoS) via CPU exhaustion. When the library decrypts a JSON Web Encryption (JWE) token using Password-Based Encryption (PBES2) algorithms, it reads the p2c (PBES2 Count) parameter directly from the token's protected header. This parameter defines the number of iterations for the PBKDF2 key derivation function. Because joserfc does not validate or bound this value, an attacker can specify an extremely large iteration count (e.g., 2^31 - 1), forcing the server to expend massive CPU resources processing a single token. This vulnerability exists at the JWA layer and impacts all high-level JWE and JWT decryption interfaces if PBES2 algorithms are allowed by the application's policy.

CVSS 7.5 · High · EPSS 0.3% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • joserfc

    Versions
    • <= 1.6.2: 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
    Affected ranges
    • ECOSYSTEM: < 1.6.3-1

    Update to 1.6.3-1

  • 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
    Affected ranges
    • ECOSYSTEM: < 1.6.3

    Update to 1.6.3

  • joserfc Ubuntu:25.10

    Versions
    • 1.0.4-1
    • 1.1.0-1
    • 1.2.0-1
    • 1.2.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • joserfc Ubuntu:26.10

    Versions
    • 1.6.2-1
    • 1.6.5-1
    • 1.6.8-1
    • 1.7.0-1
    • 1.7.1-1
    • 1.7.2-1
    • 1.7.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • 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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