CVE-2026-119194 pyasn1: Quadratic CPU use in schemaless BER/CER/DER container decoding
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-119194?
CVE-2026-119194 is a high-severity vulnerability in pyasn1, published on 29 Oct 2026.
Official 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.
Weakness: CWE-407
Which versions are affected by CVE-2026-119194?
How do I fix CVE-2026-119194?
No fix has been published for CVE-2026-119194 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-119194 being exploited?
There is no known exploitation of CVE-2026-119194 in the wild and no public exploit code.