VULNERABILITY INTELLIGENCE

CVE-2026-59884

CVSS score7.5 HIGH
EPSS probability0.62%
CISA KEVNot currently listed
Published2026-07-14
Last modified2026-07-21
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Description

pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.

Weakness classification

  • security-advisories@github.com: CWE-400

Primary references