CVE-2026-102925: virtualenv bash and fish activation scripts execute commands embedded in paths
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.7.13, the generated activate (bash and zsh) and activate.fish scripts place values already escaped by shlex.quote inside an additional quoted context. In the bash and zsh script, a crafted virtual environment path reaches VIRTUALENV when a relocated environment's recorded directory is absent; in the fish script, crafted Tcl or Tk library paths reach TCLLIBRARY or TKLIBRARY. The surplus quotes can terminate the data-only quoted run and leave shell metacharacters parsed as commands when a user sources the activation script, allowing code execution with that user's privileges. This issue is fixed in version 21.7.13.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
virtualenvto a version that resolves this vulnerability.Fixed in 21.7.13
Event History
Frequently Asked Questions
Who is exposed to exploitation?
Users who source a generated bash, zsh, or fish activation script from a virtual environment whose relevant path values have been crafted are exposed. Successful execution occurs with the privileges of the user sourcing the script.
What interaction is required for exploitation?
An attacker must cause a user to source the affected activation script. For bash and zsh, exploitation involves a relocated environment whose recorded directory is absent; for fish, crafted Tcl or Tk library paths are involved.
Are all virtualenv activation scripts affected?
The issue affects generated activate scripts for bash and zsh and activate.fish. The described bash and zsh condition requires a relocated environment with its recorded directory absent, while the fish condition concerns Tcl or Tk library path values.
What version fixes the issue?
Upgrade virtualenv to version 21.7.13 or later. Versions prior to 21.7.13 are affected by the described quoting flaw.