PYSEC-2026-3456

    Dashboard / Vulnerabilities / PYSEC-2026-3456

    PYSEC-2026-3456

    Published: 14 Jul 2026Last Modified: 22 Jul 2026

    Summary:

    Details: 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.

    References: https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4, https://github.com/pyasn1/pyasn1/security/advisories/GHSA-8ppf-4f7h-5ppj, https://github.com/pyasn1/pyasn1/commit/45bdb19eb7df4b3780fe9c912c63e99bffc39dd9

    Affected packages

    Package

    Name: pyasn1

    Purl: pkg:pypi/pyasn1

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -0.6.4

    Affected versions

    0.0.10a
    0.0.11a
    0.0.12a
    0.0.13
    0.0.13a
    0.0.13b
    0.0.6a
    0.0.9a

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    PYSEC-2026-3456 | CVE-DB