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CVE-2026-119194

CVE-2026-119194 · pyasn1: Quadratic CPU use in schemaless BER/CER/DER container decoding

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

pyasn1 is a generic ASN.1 library for Python. From 0.3.3 until 0.6.5, schemaless container decoding stores every decoded component's TagSet in a growing set even though only one-versus-multiple tag types must be distinguished. Attacker-controlled BER, CER, or DER input contains many distinct long tag IDs whose TagSet hashes collide. Each later set insertion compares against an increasing number of earlier colliding tags in ConstructedPayloadDecoderBase._decodeComponentsSchemaless, producing quadratic CPU work while decoded values and order remain valid. Repeated inputs can exhaust decoder CPU and reduce service availability. This issue is fixed in version 0.6.5.

CVSS 7.5 · High · EPSS 0.4% · Public exploit · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • pyasn1

    Versions
    • >= 0.3.3, < 0.6.5: Affected

    No fix published

  • pyasn1 Debian:12

    Versions
    • 0.4.8-3
    • 0.4.8-3+deb12u1
    • 0.4.8-3+deb12u2
    • 0.4.8-3+deb12u3
    • 0.4.8-4
    • 0.5.1-1
    • 0.6.0-1
    • 0.6.1-1
    • 0.6.2-1
    • 0.6.2-1~bpo13+1
    • 0.6.3-1
    • 0.6.4-1
    • 0.6.4-1~bpo13+1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Debian:13

    Versions
    • 0.6.1-1
    • 0.6.1-1+deb13u1
    • 0.6.1-1+deb13u2
    • 0.6.1-1+deb13u3
    • 0.6.2-1
    • 0.6.2-1~bpo13+1
    • 0.6.3-1
    • 0.6.4-1
    • 0.6.4-1~bpo13+1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Debian:14

    Versions
    • 0.6.1-1
    • 0.6.2-1
    • 0.6.2-1~bpo13+1
    • 0.6.3-1
    • 0.6.4-1
    • 0.6.4-1~bpo13+1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 PyPI

    Versions
    • 0.3.3
    • 0.3.4
    • 0.3.5
    • 0.3.6
    • 0.3.7
    • 0.4.1
    • 0.4.2
    • 0.4.3
    • 0.4.4
    • 0.4.5
    • 0.4.6
    • 0.4.7
    • 0.4.8
    • 0.5.0
    • 0.5.1
    • 0.6.0
    • 0.6.1
    • 0.6.2
    • 0.6.3
    • 0.6.4
    Affected ranges
    • ECOSYSTEM: ≥ 0.3.3, < 0.6.5

    Update to 0.6.5

  • pyasn1 Ubuntu:Pro:14.04:LTS

    Versions
    • 0.1.4-0ubuntu1
    • 0.1.7-1ubuntu1
    • 0.1.7-1ubuntu2
    • 0.1.7-1ubuntu2.1
    • 0.1.7-1ubuntu2.1+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Ubuntu:Pro:16.04:LTS

    Versions
    • 0.1.8-2
    • 0.1.9-1
    • 0.1.9-1ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Ubuntu:Pro:18.04:LTS

    Versions
    • 0.1.9-2
    • 0.4.2-3
    • 0.4.2-3ubuntu0.18.04.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Ubuntu:Pro:20.04:LTS

    Versions
    • 0.4.2-3
    • 0.4.2-3build1
    • 0.4.2-3ubuntu0.20.04.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Ubuntu:22.04:LTS

    Versions
    • 0.4.8-1
    • 0.4.8-1ubuntu0.1
    • 0.4.8-1ubuntu0.2
    • 0.4.8-1ubuntu0.3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Ubuntu:24.04:LTS

    Versions
    • 0.4.8-4
    • 0.4.8-4ubuntu0.1
    • 0.4.8-4ubuntu0.2
    • 0.4.8-4ubuntu0.3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Ubuntu:26.10

    Versions
    • 0.6.3-1
    • 0.6.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • pyasn1 Ubuntu:26.04:LTS

    Versions
    • 0.6.1-1
    • 0.6.1-1build1
    • 0.6.2-1
    • 0.6.3-1
    • 0.6.3-1ubuntu0.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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