Performance Impact from Real Type Conversion in Python ASN.1 Library
CVE-2026-59886

7.5HIGH

Key Information:

Vendor

Pyasn1

Status
Pyasn1
Vendor
CVE Published:
14 July 2026

What is CVE-2026-59886?

The pyasn1 library, an ASN.1 implementation for Python, suffers from a performance issue where its univ.Real type performs inefficient float conversions. Before version 0.6.4, the library's handling of large exponents in REAL values can lead to excessive CPU and memory usage when decoding ASN.1 data that is not trusted. The problem arises during operations such as prettyPrint, string conversion, and numeric comparisons, potentially causing application hangs. The issue has been addressed in version 0.6.4.

Affected Version(s)

pyasn1 < 0.6.4

References

https://github.com/pyasn1/pyasn1/security/advisories/GHSA...
x_refsource_CONFIRM
https://github.com/pyasn1/pyasn1/commit/e60c691cb91addb8f...
x_refsource_MISC
https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4
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

.