fflate unzipSync can enter an infinite loop when parsing malformed ZIP64 archives
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.
01
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-45820US | high7.5 | — | ||
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=0xFFFFFF… | ||||
02
references
External citations — patches, advisories, analysis.
- https://github.com/101arrowz/fflatePACKAGE
- https://github.com/101arrowz/fflate/blob/f7873560ad229c22c4b23b06c6a3806ffde77569/src/index.ts#L2714WEB
- https://github.com/101arrowz/fflate/commit/e6d5e6e1076892f72770ac732d83c81da9f3316eWEB
- https://github.com/101arrowz/fflate/releases/tag/v0.8.3WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-45820ADVISORY
scry
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