PT-2026-58107 · Pyasn1 · Pyasn1

Published 2026-07-14 · Updated 2026-07-14 · CVE-2026-59886

Mitre

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the univ.Real type converted its mantissa, base, and exponent value to a Python float using exact big-integer exponentiation. A BER, CER, or DER encoded REAL value only a few bytes long can carry a very large exponent, causing float conversion through prettyPrint(), str(), comparison, arithmetic, int(), or an explicit float() call to consume excessive CPU and memory and hang applications that decode untrusted ASN.1 data and then print, log, or compare decoded objects. This issue is fixed in version 0.6.4.

Fix

Resource Exhaustion

Allocation of Resources Without Limits

Weakness Enumeration

CWE-400

CWE-770

Related Identifiers

CVE-2026-59886

Affected Products

Pyasn1

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-59886 · Security Note
• https://github.com/pyasn1/pyasn1/security/advisories/GHSA-hm4w-wwcw-mr6r · Note
• https://github.com/pyasn1/pyasn1/commit/e60c691cb91addb8fcefa2f537e85ede6fb1e886 · Note
• https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4 · Note