proot-distro install has a Symlink Escape (Arbitrary Host File Write) via Malicious Tar Archive

Exploitation

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

CVSS

8.2 · CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

EPSS

• CVE-2026-54574: 0.21% estimated exploitation activity in the next 30 days; percentile 11.86 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Repository: termux/proot-distro Component: prootdistro/commands/install.py → extractplaintar(); also helpers/docker.py → applylayer() --- Affected Versions | Component | Version | |---------------|------------------------------| | proot-distro | 5.0.2 (confirmed vulnerable) | | Termux app | 0.119.0-beta.3 | | Device / ABI | Samsung Galaxy A23 / aarch64 | | Python (host) | 3.13 | --- Vulnerability Description proot-distro install extracts a plain tarball rootfs by calling extractplaintar() in prootdistro/commands/install.py. This function correctly rejects tar member names containing .. components, but applies no equivalent check on symlink targets (member.linkname). A tar archive can therefore: 1. Plant a symlink inside the rootfs whose target is an absolute host path (e.g. /data/data/com.termux/files/home). 2. Write a subsequent regular-file member whose path traverses through that symlink name. Python's open() follows the symlink, writing the file on the host filesystem at the…

Published by the source

29 Jul 2026, 16:32 UTC

Last modified by the source

29 Jul 2026, 16:32 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-9xq3-3fqg-4vg7

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# Patch Next advisory brief: CVE-2026-54574

Advisory: `proot-distro install` has a Symlink Escape (Arbitrary Host File Write) via Malicious Tar Archive
IDs: CVE-2026-54574, GHSA-9xq3-3fqg-4vg7
Record: https://patchnext.com/advisories/cve-2026-54574 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: proot-distro 5.1.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI proot-distro: affected <= 5.1.4; fixed in 5.1.5

## Suggested inspection (read-only)
- `python -m pip show proot-distro`: 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 proot-distro.
- 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-9xq3-3fqg-4vg7 (GitHub-reviewed advisory GHSA-9xq3-3fqg-4vg7 lists affected ranges: PyPI proot-distro >=0 <=5.1.4)

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