VulnerabilityAnalyzed
CVE-2026-45820
fflate through 0.8.2 is vulnerable to denial of service via an infinite loop in unzipSync().
MEDIUM 6.6EPSS 0.28%
Does this matter?
Lower severity and a low EPSS score (0.28%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 6.6 MEDIUMCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.28% probability · 20th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-835
- Affected
- 101arrowz/fflate
- Source
- 22e2d327-25fe-45d7-9f0c-dcd23b7108df
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.