Resource exhaustion in 101arrowz Fflate

CVE-2026-45820

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.

Vulnerability class: DoS (Denial of Service)

EPSS: 0.003 (20.0th percentile) — read the EPSS interpretation.