CVE-2026-113721: virtualenv · Generated files can follow existing destination links
Affects poetrySource GCVE Database
Not known to be exploited · CVSS 4.5 Medium : upgrade to 2.5.1_1 or 1.2.2_1 when convenient.
Data as of 30 Oct 2026, 08:29 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 4.5 |
|---|
- Patch
- Available – fixed in 2.5.1_1, 1.2.2_1
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:LExploitation evidence
Disclosed: evidence found.
CVE published 20 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade poetry to 2.5.1_1 or 1.2.2_1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewpoetrypkg:brew/poetryOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied by upgrading virtualenv to version 1.2.2_1 or later, or 2.5.1_1 or later. The fix replaces pre-existing output links and uses exclusive file creation to prevent writing through dangling symlinks. Until patched, ensure that untrusted users cannot prepare symbolic or hard links in the destination directory where virtual environments are created, and verify that the invoking user does not have write permissions on potentially linked targets outside the environment.
Description
CVE-2026-113721 is a vulnerability in virtualenv where generated activation files and pyvenv.cfg can follow existing symbolic links and write outside the intended environment. This occurs because the code checks for file existence without handling dangling symlinks properly, allowing writes to arbitrary locations if an attacker can prepare links beforehand. The issue affects environment creation and seeding files, potentially overwriting files outside the virtual environment. The vulnerability requires that another user can place links in the destination and that the invoking user has write permissions to the linked targets. A fix is available in versions 1.2.2_1 and 2.5.1_1.
References
- github.com/pypa/virtualenv/security/advisories/GHSA-558c-9hv2-4prj (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-113721 (opens in a new tab)
- github.com/pypa/virtualenv/pull/3431 (opens in a new tab)
- github.com/pypa/virtualenv/commit/d25f28699eefb1fc34a251e5adf2b5de844c36cd (opens in a new tab)
- github.com/pypa/virtualenv (opens in a new tab)
- github.com/pypa/virtualenv/releases/tag/21.14.9 (opens in a new tab)