PYSEC-2026-3457

    Dashboard / Vulnerabilities / PYSEC-2026-3457

    PYSEC-2026-3457

    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 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.

    References: https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4, https://github.com/pyasn1/pyasn1/security/advisories/GHSA-hm4w-wwcw-mr6r, https://github.com/pyasn1/pyasn1/commit/e60c691cb91addb8fcefa2f537e85ede6fb1e886

    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-2026-3457 | CVE-DB