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.
- CVSS 4.0
- 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 - CVSS 3.1
- 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 20% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-400, CWE-835
- Published
- Modified
- Record from
- the NVD, synced
Affected
- 101arrowz:fflate
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-px8p-9vwx-vf98 | npm | fflate | >=0.4.5 <0.4.9 | 0.4.9 |
| GHSA-px8p-9vwx-vf98 | npm | fflate | >=0.5.0 <0.5.4 | 0.5.4 |
| GHSA-px8p-9vwx-vf98 | npm | fflate | >=0.6.0 <0.6.11 | 0.6.11 |
| GHSA-px8p-9vwx-vf98 | npm | fflate | >=0.7.0 <0.7.5 | 0.7.5 |
| GHSA-px8p-9vwx-vf98 | npm | fflate | >=0.8.0 <0.8.3 | 0.8.3 |