PYSEC-2026-1837

    Dashboard / Vulnerabilities / PYSEC-2026-1837

    PYSEC-2026-1837

    Published: 7 Jul 2026Last Modified: 7 Jul 2026

    Summary: PyPDF2 quadratic runtime with malformed PDF missing xref marker

    Details: ### Impact An attacker who uses this vulnerability can craft a PDF which leads to unexpected long runtime. This quadratic runtime blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. ### Patches https://github.com/py-pdf/pypdf/pull/808 ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ ### References * [PyPDF2 PR #808](https://github.com/py-pdf/pypdf/pull/808) * [PyPDF2 Issue #582](https://github.com/py-pdf/pypdf/issues/582)

    References: https://github.com/py-pdf/pypdf/security/advisories/GHSA-jrm6-h9cq-8gqw, https://nvd.nist.gov/vuln/detail/CVE-2023-36810, https://github.com/py-pdf/pypdf/issues/582, https://github.com/py-pdf/pypdf/pull/808, https://github.com/py-pdf/pypdf/commit/c6c56f550bb384e05f0139c796ba1308837d6373, https://github.com/py-pdf/pypdf, https://lists.debian.org/debian-lts-announce/2023/07/msg00019.html, https://pypi.org/project/pypdf2, https://github.com/advisories/GHSA-jrm6-h9cq-8gqw

    Affected packages

    Package

    Name: pypdf2

    Purl: pkg:pypi/pypdf2

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1.27.9

    Affected versions

    1.15

    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-2026-1837 | CVE-DB