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CVE-2026-39373

CVE-2026-39373 · JWCrypto: JWE ZIP decompression bomb

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

JWCrypto implements JWK, JWS, and JWE specifications using python-cryptography. Prior to 1.5.7, an unauthenticated attacker can exhaust server memory by sending crafted JWE tokens with ZIP compression. The existing patch for CVE-2024-28102 limits input token size to 250KB but does not validate the decompressed output size. An unauthenticated attacker can cause memory exhaustion on memory-constrained systems. A token under the 250KB input limit can decompress to approximately 100MB. This vulnerability is fixed in 1.5.7.

CVSS 5.3 · Medium · EPSS 0.3% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • jwcrypto

    Versions
    • < 1.5.7: Affected

    No fix published

  • python-jwcrypto Debian:12

    Versions
    • 1.1.0-1
    • 1.1.0-1+deb12u1
    • 1.5.4-1
    • 1.5.6-1
    • 1.5.6-1.1
    • 1.5.6-1.1~deb13u1
    • 1.5.6-1.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Debian:13

    Versions
    • 1.5.6-1
    Affected ranges
    • ECOSYSTEM: < 1.5.6-1.1~deb13u1

    Update to 1.5.6-1.1~deb13u1

  • python-jwcrypto Debian:14

    Versions
    • 1.5.6-1
    • 1.5.6-1.1~deb13u1
    Affected ranges
    • ECOSYSTEM: < 1.5.6-1.1

    Update to 1.5.6-1.1

  • jwcrypto PyPI

    Versions
    • 0.2.0
    • 0.2.1
    • 0.3.0
    • 0.3.1
    • 0.4.0
    • 0.4.1
    • 0.4.2
    • 0.5.0
    • 0.6.0
    • 0.7
    • 0.8
    • 0.9
    • 0.9.1
    • 1.0
    • 1.2
    • 1.3
    • 1.3.1
    • 1.4
    • 1.4.1
    • 1.4.2
    • 1.5.0
    • 1.5.1
    • 1.5.2
    • 1.5.3
    • 1.5.4
    • 1.5.5
    • 1.5.6
    Affected ranges
    • ECOSYSTEM: < 1.5.7

    Update to 1.5.7

  • python-jwcrypto Ubuntu:16.04:LTS

    Versions
    • 0.2.1-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Ubuntu:18.04:LTS

    Versions
    • 0.3.2-1
    • 0.4.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Ubuntu:20.04:LTS

    Versions
    • 0.6.0-1
    • 0.6.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Ubuntu:22.04:LTS

    Versions
    • 0.8.0-1
    • 1.0.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Ubuntu:24.04:LTS

    Versions
    • 1.1.0-1
    • 1.5.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Ubuntu:25.10

    Versions
    • 1.5.6-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Ubuntu:26.10

    Versions
    • 1.5.6-1
    • 1.5.6-1.1
    • 1.5.6-1.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-jwcrypto Ubuntu:26.04:LTS

    Versions
    • 1.5.6-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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