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

> Attackers can write arbitrary files outside the cache directory via crafted TAR archives in Cornac dataset loaders, potentially compromising the host filesystem.

- **Severity:** High 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jul 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-rrh3-cwwj-g5mg

## What is CVE-2026-43637?

CVE-2026-43637 is a high-severity path traversal vulnerability in PreferredAI cornac, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-43637?


## How do I fix CVE-2026-43637?

No fix has been published for CVE-2026-43637 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-43637 being exploited?

There is no known exploitation of CVE-2026-43637 in the wild and no public exploit code.

Public exploit code:

- Path traversal (Tar Slip) in Cornac via _extract_archive (CVE-2026-43637) (github_poc): https://github.com/rahulreddykarne/CVE-2026-43637-cornac

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43637 and fix it if it is affected.

What it is: CVE-2026-43637 is a high-severity path traversal vulnerability in PreferredAI cornac, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43637 in the wild and no public exploit code.

Affected product: PreferredAI cornac. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43637/ (Markdown: https://insights.sbomify.com/CVE-2026-43637/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43637
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43637
- OSV: https://osv.dev/vulnerability/CVE-2026-43637

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43637/
Summaries are generated and may contain mistakes; the official description above is the record.