CVE-2026-59885highCWE-400CWE-407

CVE-2026-59885: high-severity vulnerability in pyasn1

pyasn1: Quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denial of service

Published

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.5epss 0.6%
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue is fixed in version 0.6.4.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
pyasn1 · pyasn1
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