CVE-2026-102925

Impact

The generated activate (bash/zsh) and activate.fish scripts interpolate a shlex.quote-ed value into a position that quotes it a second time. The extra quotes terminate the quoted run early and leave part of the value parsed as shell code, so a path containing shell metacharacters runs commands when a user sources the activation script.

activate is affected through the virtual environment's own path, on the branch that reports a relocated environment:

echo "Virtual environment directory __VIRTUAL_ENV__ does not exist!" >&2

For a destination named x'$(id)'y, shlex.quote emits 'x'"'"'$(id)'"'"'y'. The inner " closes the enclosing double quote and $(id) is left unquoted. Backtick and ; payloads reach the same result. This branch runs whenever the recorded path is absent, which is the normal case for a virtual environment copied or distributed to another machine.

activate.fish is affected through the interpreter's Tcl/Tk library paths:

set -gx TCL_LIBRARY '__TCL_LIBRARY__'

shlex.quote already returns '/tcl/(cmd)/lib', so the rendered line is ''/tcl/(cmd)/lib''. fish concatenates the adjacent quoted runs and expands the (cmd) left between them. The same doubling also splits a path containing a space into two list elements, corrupting TCL_LIBRARY and TK_LIBRARY.

This is the same defect class as GHSA-x78j-v8h9-3j2q, which covered activate.bat.

Patches

Fixed in 21.7.13 by moving the placeholders outside the surrounding quotes, so each value keeps only the quoting shlex.quote applied. Fix: https://github.com/pypa/virtualenv/pull/3252

Workarounds

Avoid creating or distributing virtual environments whose path contains ', `, $, ;, ( or ), and inspect the generated activation script before sourcing one you did not create.

The generated activate (bash/zsh) and activate.fish scripts interpolate a shlex.quote-ed value into a position that quotes it a second time. The extra quotes terminate the quoted run early and leave part of the value parsed as shell code, so a path containing shell metacharacters runs commands when a user sources the activation script.

activate is affected through the virtual environment's own path, on the branch that reports a relocated environment (Virtual environment directory __VIRTUAL_ENV__ does not exist!). For a destination named x'$(id)'y, shlex.quote emits 'x'"'"'$(id)'"'"'y'; the inner " closes the enclosing double quote and $(id) is left unquoted. This branch runs whenever the recorded path is absent, which is the normal case for a virtual environment copied or distributed to another machine.

activate.fish is affected through the interpreter's Tcl/Tk library paths (set -gx TCL_LIBRARY '__TCL_LIBRARY__'). The rendered line becomes ''/tcl/(cmd)/lib'', and fish expands the (cmd) left between the adjacent quoted runs. The same doubling splits a path containing a space into two list elements, corrupting TCL_LIBRARY and TK_LIBRARY.

This is the same defect class as GHSA-x78j-v8h9-3j2q, which covered activate.bat.

Fixed in 21.7.13 by moving the placeholders outside the surrounding quotes, so each value keeps only the quoting shlex.quote applied.

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 VIRTUAL_ENV when a relocated environment's recorded directory is absent; in the fish script, crafted Tcl or Tk library paths reach TCL_LIBRARY or TK_LIBRARY. 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.

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 VIRTUAL_ENV when a relocated environment's recorded directory is absent; in the fish script, crafted Tcl or Tk library paths reach TCL_LIBRARY or TK_LIBRARY. 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.

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 VIRTUAL_ENV when a relocated environment's recorded directory is absent; in the fish script, crafted Tcl or Tk library paths reach TCL_LIBRARY or TK_LIBRARY. 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.

TuxCare rebuilt virtualenv to address 4 CVEs. Fixed in 20.39.1.post2+tuxcare.

These are all security issues fixed in the python313-virtualenv-21.14.2-1.1 package on the GA media of openSUSE Tumbleweed.

Root has patched CVE-2026-102925 in the virtualenv package for Root:PyPI. Multiple fixed versions available.