CVE-2023-36807

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    CVE-2023-36807

    Published: 30 Jun 2023Last Modified: 12 Aug 2026

    Summary: Infinite Loop when reading malformed objects in pypdf

    Details: pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. In version 2.10.5 an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the user extracted metadata from such a malformed PDF. Versions prior to 2.10.5 throw an error, but do not hang forever. This issue was fixed with https://github.com/py-pdf/pypdf/pull/1331 which has been included in release 2.10.6. Users are advised to upgrade. Users unable to upgrade should modify `PyPDF2/generic/_data_structures.py::read_object` to an an error throwing case. See GHSA-hm9v-vj3r-r55m for details.

    References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/36xxx/CVE-2023-36807.json, https://github.com/py-pdf/pypdf/security/advisories/GHSA-hm9v-vj3r-r55m, https://nvd.nist.gov/vuln/detail/CVE-2023-36807, https://github.com/py-pdf/pypdf/issues/1329, https://github.com/py-pdf/pypdf/pull/1331

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 4073b2a36ef476b865e927f4c84be4bedd21f0f8
    Fixed -None

    Affected versions

    2.10.5

    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-2023-36807 | CVE-DB