CVE-2026-85396
rubyzip versions before 3.4.0 contain a path traversal vulnerability in Zip::Entry#extract that fails to properly validate extraction paths using prefix comparison without trailing separators.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
rubyzip versions before 3.4.0 contain a path traversal vulnerability in Zip::Entry#extract that fails to properly validate extraction paths using prefix comparison without trailing separators. Attackers can craft archive entries with names like ../upload_backup/owned.sh to write files outside the intended extraction directory into sibling paths sharing the destination prefix.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.38% probability · 32th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Source
- disclosure@vulncheck.com
References
- https://github.com/geo-chen/oss/blob/main/rubyzip.md
- https://github.com/rubyzip/rubyzip
- https://github.com/rubyzip/rubyzip/blob/v3.3.1/lib/zip/entry.rb
- https://github.com/rubyzip/rubyzip/commit/17edfbf4423b83211b075acc23a7d8640da63449
- https://github.com/rubyzip/rubyzip/releases/tag/v3.4.0
- https://www.vulncheck.com/advisories/rubyzip-before-3.4.0-path-traversal-in-zip-entry-extract-via-sibling-directory-prefix
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.