Vulnerability · Published Oct 20, 2026 · Assigned by GitHub_M
CVE-2026-113724virtualenv: Deletion recovery can change a symlink target's mode
Medium 4.5
In plain English
A medium-severity security flaw in virtualenv from pypa. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the safe_delete() deletion error handler responds to a failed removal by reading mode bits with os.lstat(path) and applying owner-write permission with os.chmod(path, ...), which follows a symlink. A planted link inside a read-only directory can therefore cause a victim-owned target outside the destination that is initially not writable by the invoking user to become broadly writable before the retry fails, provided that user owns the target and can change its mode. Another account can use the widened mode only if it can traverse the target's parent directories; root does not reach the demonstrated failure path, and the operation does not itself read the target. This issue is fixed in version 21.14.9.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-virtualenv | no fix listed | DEBIAN-CVE-2026-113724 |
| Debian:13 | python-virtualenv | no fix listed | DEBIAN-CVE-2026-113724 |
| Debian:14 | python-virtualenv | no fix listed | DEBIAN-CVE-2026-113724 |
| PyPI | virtualenv | 21.14.9 | GHSA-43mp-35q3-x3fq |
| Ubuntu:26.04:LTS | python-virtualenv | no fix listed | UBUNTU-CVE-2026-113724 |
| Ubuntu:26.10 | python-virtualenv | no fix listed | UBUNTU-CVE-2026-113724 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| pypa | virtualenv | < 21.14.9 |
Weakness: CWE-59 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
References
- https://github.com/pypa/virtualenv/security/advisories/GHSA-43mp-35q3-x3fq x_refsource_CONFIRM
- https://github.com/pypa/virtualenv/pull/3427 x_refsource_MISC
- https://github.com/pypa/virtualenv/commit/2bfdc0230d1b2685fedfcfe66c835b9a2ec7c440 x_refsource_MISC
- https://github.com/pypa/virtualenv/releases/tag/21.14.9 x_refsource_MISC