CVE-2026-54727: Container Isolation Bypass in proot-distro via Malicious Restore Archive
Vulnerability ID: CVE-2026-54727
CVSS Score: 8.2
Published: 2026-07-29
A container isolation bypass vulnerability exists in proot-distro prior to version 5.1.6. The utility accepted hardlink entries pointing outside the container directory being restored, allowing cross-container file read and write capabilities.
TL;DR
A container boundary bypass in proot-distro allows a malicious restore archive to read or write files inside other isolated containers on the device.
⚠️ Exploit Status: POC
Technical Details
- CWE ID: CWE-668
- Attack Vector: Local
- CVSS Score: 8.2 (High)
- Impact: Cross-container read and write access
- Exploit Status: Proof-of-Concept
- KEV Status: Not Listed
Affected Systems
- proot-distro
-
proot-distro: < 5.1.6 (Fixed in:
5.1.6)
Code Analysis
Commit: 98aff32
Enforce single-container extraction limits and restrict hardlink resolution targets inside the active container directory
Commit: 6f73f98
Ensure atomic verification of rootfs locations before filesystem writes are performed
Commit: 50cba9f
Enforce validation to confirm a real directory was extracted at the rootfs destination path
Commit: eb1dbf8
Update container name regex pattern validation to use end-of-string anchor \Z
Exploit Details
- GitHub Security Advisory: Details the logical flaw concerning hardlink destination validation inside rootless container environments.
Mitigation Strategies
- Keep proot-distro updated to the latest version via Termux package management
- Do not restore unauthenticated, third-party, or untrusted container backup archives
- Enforce static analysis or pre-extraction checks on backup tarballs
Remediation Steps:
- Execute 'pkg update && pkg upgrade proot-distro' to upgrade to v5.1.6 or later
- Audit any existing container layouts or verify nested hardlink/symlink properties
- Configure automated package scanners to flag outdated variants of proot-distro
References
Read the full report for CVE-2026-54727 on our website for more details including interactive diagrams and full exploit analysis.
Top comments (1)
The container isolation bypass vulnerability in proot-distro, specifically the acceptance of hardlink entries pointing outside the container directory being restored, highlights the importance of proper input validation and sanitization. I noticed that the fix involved enforcing single-container extraction limits and restricting hardlink resolution targets inside the active container directory, as seen in commit 98aff32. This makes me wonder, have there been any considerations for implementing additional security measures, such as runtime monitoring or anomaly detection, to further prevent potential bypass attempts?