CVE-2026-119196

    Dashboard / Vulnerabilities / CVE-2026-119196

    CVE-2026-119196

    Published: 29 Oct 2026Last Modified: 5 Nov 2026

    Summary: pyasn1: Quadratic CPU consumption in constructed BIT STRING decoding

    Details: pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, constructed BIT STRING decoding repeatedly shifts and copies the complete bit value accumulated from earlier fragments. Attacker-controlled BER or CER input contains many constructed BIT STRING fragments; schema-driven DER also accepts a definite-length constructed BIT STRING. BitStringPayloadDecoder repeatedly calls BitString.fromOctetString with the prior bitString as prepend, shifting an ever-growing SizedInteger for each fragment and causing quadratic work. Large fragmented values can exhaust CPU during decode() without requiring later conversion or formatting. This issue is fixed in version 0.6.5.

    References: https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/119xxx/CVE-2026-119196.json, https://github.com/pyasn1/pyasn1/security/advisories/GHSA-2qm8-x737-gmw5, https://nvd.nist.gov/vuln/detail/CVE-2026-119196, https://github.com/pyasn1/pyasn1/commit/73ba7b043cc7e92cb37f16f2c955bff93b0e6f6c, https://github.com/pyasn1/pyasn1/pull/132

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -5d1673657b729fb580467e2cf4875856bbca5e59

    Affected versions

    v0.6.4
    v0.6.3
    v0.6.2
    v0.6.1
    v0.6.0

    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
    CVE-2026-119196 | CVE-DB