101arrowz/fflate · Security
fflate unzipSync can enter an infinite loop when parsing malformed ZIP64 archives
- GHSA ID
- GHSA-px8p-9vwx-vf98
- CVE ID
- CVE-2026-45820
- Severity
- medium
- Published
- Updated
- CVSS
- 7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CVSS v3
- 7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CVSS v4
- 6.6 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/S:N/AU:Y/R:U/V:D/RE:M/U:Amber
Description
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.
CWEs
- CWE-400 · Uncontrolled Resource Consumption
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-45820 ↗
- https://github.com/101arrowz/fflate/blob/f7873560ad229c22c4b23b06c6a3806ffde77569/src/index.ts#L2714 ↗
- https://github.com/101arrowz/fflate/commit/e6d5e6e1076892f72770ac732d83c81da9f3316e ↗
- https://github.com/101arrowz/fflate/releases/tag/v0.8.3 ↗
- https://github.com/advisories/GHSA-px8p-9vwx-vf98 ↗