schemaless BER/CER/DER container decoding · pyasn1: Quadratic CPU use
Affects MicrosoftSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 3 Nov 2026, 10:57 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 7.5 |
|---|
- 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 29 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 3 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
PyPIpyasn1pkg:pypi/pyasn1Other threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should monitor vendor advisories for updates. Until a fix is released, consider limiting exposure to untrusted ASN.1 data inputs or applying application-level resource constraints to mitigate potential CPU exhaustion.
Description
A vulnerability in pyasn1 version 3.0 causes quadratic CPU usage during schemaless BER/CER/DER container decoding. This can lead to excessive CPU consumption when processing certain ASN.1 encoded data without schema validation.