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VulnerabilityPublished Updated

CVE-2026-119194: pyasn1 is a generic ASN.1 library for Python

Affects pyasn1Source GCVE Database

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Authoritative record:CVE-2026-119194· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in 0.6.5 : patch pyasn1 soon.

Data as of 5 Nov 2026, 12:35 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 3.17.5
Patch
Available – fixed in 0.6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.10pyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=stonkingOther threatsAffected
  • =0.6.3-1
  • =0.6.4-1
Fixed in–
Ubuntu 26.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=resoluteOther threatsAffected
  • 0.6.1-1 – 0.6.3-1ubuntu0.1
5 affected builds
Fixed in–
Ubuntu 24.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=nobleOther threatsAffected
  • 0.4.8-4 – 0.4.8-4ubuntu0.3
4 affected builds
Fixed in–
Ubuntu 22.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=jammyOther threatsAffected
  • 0.4.8-1 – 0.4.8-1ubuntu0.3
4 affected builds
Fixed in–
Ubuntu Pro 20.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=esm-infra/focalOther threatsAffected
  • =0.4.2-3
  • =0.4.2-3build1
  • =0.4.2-3ubuntu0.20.04.1~esm1
Fixed in–
Ubuntu Pro 18.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=esm-infra/bionicOther threatsAffected
  • =0.1.9-2
  • =0.4.2-3
  • =0.4.2-3ubuntu0.18.04.1~esm1
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

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.

References

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