Cornac: Path Traversal via _extract_archive() in download.py

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.8 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-43637: 0.66% estimated exploitation activity in the next 30 days; percentile 51.99 (FIRST EPSS, 2026-11-10). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Cornac before 2.6.0 contains a path traversal (Tar Slip) vulnerability that allows attackers to write arbitrary files outside the intended cache directory by supplying a crafted TAR archive containing ../ sequences, absolute paths, or symlink/hardlink entries to the _extract_archive() function in cornac/utils/download.py. Attackers can trigger this vulnerability through the built-in dataset loaders, which automatically download and extract archives, causing archive.extractall() to write files to arbitrary locations on the filesystem accessible to the running process.

Published by the source

15 Jul 2026, 15:33 UTC

Last modified by the source

9 Nov 2026, 22:00 UTC

Source last checked

10 Nov 2026, 06:35 UTC

1. Revision 2 · amended · 10 Nov 2026

   Amended from osv record GHSA-rrh3-cwwj-g5mg

2. Revision 1 · created · 9 Nov 2026

   Published from ghsa record GHSA-rrh3-cwwj-g5mg

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# Patch Next advisory brief: CVE-2026-43637

Advisory: Cornac: Path Traversal via _extract_archive() in download.py
IDs: CVE-2026-43637, GHSA-rrh3-cwwj-g5mg
Record: https://patchnext.com/advisories/cve-2026-43637 (revision 2, source checked 10 Nov 2026, 06:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: cornac 2.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI cornac: affected < 2.6.0; fixed in 2.6.0

## Suggested inspection (read-only)
- `python -m pip show cornac`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on cornac.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rrh3-cwwj-g5mg (GitHub-reviewed advisory GHSA-rrh3-cwwj-g5mg lists affected ranges: PyPI cornac >=0 <2.6.0)
- Verified: https://osv.dev/vulnerability/GHSA-rrh3-cwwj-g5mg (OSV record GHSA-rrh3-cwwj-g5mg lists affected ranges: PyPI cornac >=0 <2.6.0 (fixed))

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