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CVE-2026-119196VulnerabilityPublished

constructed BIT STRING decoding · pyasn1: Quadratic CPU consumption

Affects MicrosoftSource GCVE Database

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Authoritative record:CVE-2026-119196· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade to 0.6.5 soon.

Data as of 31 Oct 2026, 08:50 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
EPSS
0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 30 Oct 2026.

What to do

Upgrade pyasn1 to 0.6.5.

Affected software

ProductAffectedFixed in
pyasn1pyasn1Affected
  • <0.6.5
Fixed in
  • 0.6.5
PyPIpyasn1pkg:pypi/pyasn1Other threatsAffected
  • <0.6.5
Fixed in
  • 0.6.5

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

AI-suggested

If you cannot patch yet, consider limiting exposure to untrusted inputs that require pyasn1 BIT STRING decoding or applying resource usage limits to affected processes.

Description

A vulnerability in the pyasn1 library version 3.0 causes quadratic CPU consumption during decoding of constructed BIT STRING data. This can lead to excessive CPU usage when processing crafted inputs.

References

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