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Uncontrolled Resource Consumption

CVE-2026-59884

Severity High
Score 7.5/10

Summary

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.

  • LOW
  • NETWORK
  • NONE
  • UNCHANGED
  • NONE
  • NONE
  • NONE
  • HIGH

CWE-400 - Uncontrolled resource consumption

An uncontrolled resource allocation attack (also known as resource exhaustion attack) triggers unauthorized overconsumption of the limited resources in an application, such as memory, file system storage, database connection pool entries, and CPU. This may lead to denial of service for valid users and degradation of the application's functionality as well as that of the host operating system.

Advisory Timeline

  • Published