CVE-2026-45820

Updated on 22 Jul 2026

Severity

6.6 Medium severity

Details

CVSS score
6.6
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Overview

About vulnerability

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.

Details

Affected product:
fflate , smithy-typescript
Affected packages:
fflate @ 0.8.1 (+13 more)

Fixes