GHSA-px8p-9vwx-vf98

    Dashboard / Vulnerabilities / GHSA-px8p-9vwx-vf98

    GHSA-px8p-9vwx-vf98

    Published: 22 Jul 2026Last Modified: 10 Sept 2026

    Summary: fflate unzipSync can enter an infinite loop when parsing malformed ZIP64 archives

    Details: fflate through 0.8.2 is vulnerable to denial of service via an infinite loop in unzipSync(). A crafted ZIP archive with a central directory entry declaring compressed_size=0xFFFFFFFF (ZIP64 sentinel) but missing the required ZIP64 extra field tag 0x0001 causes z64e() to loop indefinitely due to out-of-bounds reads returning undefined, which coerces to 0, keeping the loop condition permanently true.

    References: https://nvd.nist.gov/vuln/detail/CVE-2026-45820, https://github.com/101arrowz/fflate/commit/e6d5e6e1076892f72770ac732d83c81da9f3316e, https://github.com/101arrowz/fflate, https://github.com/101arrowz/fflate/blob/f7873560ad229c22c4b23b06c6a3806ffde77569/src/index.ts#L2714, https://github.com/101arrowz/fflate/releases/tag/v0.8.3

    Affected packages

    Package

    Name: fflate

    Purl: pkg:npm/fflate

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0.4.5
    Fixed -0.4.9

    Affected versions

    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
    GHSA-px8p-9vwx-vf98 | CVE-DB