Denial of Service Vulnerability in pyasn1 ASN.1 Library
CVE-2026-119194

7.5HIGH

Key Information:

Vendor

Pyasn1

Status
Pyasn1
Vendor
CVE Published:
29 October 2026

What is CVE-2026-119194?

The pyasn1 library, which provides implementations for ASN.1 data structures in Python, contains a Denial of Service vulnerability stemming from ineffectively handling schemaless container decoding. When processing attacker-controlled inputs, this vulnerability causes a significant performance degradation due to hash collisions in TagSet. As more inputs are processed, the decoding function becomes increasingly inefficient, leading to CPU exhaustion. This results in reduced service availability, affecting applications relying on pyasn1 for secure data handling. The issue has been addressed in version 0.6.5 of the library.

Affected Version(s)

pyasn1 >= 0.3.3, < 0.6.5

References

https://github.com/pyasn1/pyasn1/security/advisories/GHSA...
x_refsource_CONFIRM
https://github.com/pyasn1/pyasn1/pull/132
x_refsource_MISC
https://github.com/pyasn1/pyasn1/commit/a36e3a3d067148d26...
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.