CVE-2026-113721: virtualenv · Generated files can follow existing destination links
Affects hatchSource GCVE Database
Not known to be exploited · CVSS 4.5 Medium : upgrade to 1.18.1_2 or 1.6.2 when convenient.
Data as of 27 Oct 2026, 23:27 UTC
- Patch
- Available – fixed in 1.18.1_2, 1.6.2
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
Weaponised: 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 26 Oct 2026.
What to do
Upgrade hatch to 1.18.1_2 or 1.6.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewhatchpkg:brew/hatchOther 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 fix is available in virtualenv versions 1.6.2 and 1.18.1_2 that replaces pre-existing output links and uses exclusive creation for generated files to prevent writing through dangling symlinks. Users should upgrade to these fixed versions to remediate the vulnerability. No additional mitigation is required if the environment is updated accordingly.
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 unintended targets if an attacker can prepare links in the destination. The vulnerability requires attacker-controlled links and write permissions on the linked targets. It was fixed in versions 1.6.2 and 1.18.1_2.
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)