Summary
virtualenv bash and fish activation scripts execute commands embedded in paths
Workarounds
Avoid creating or distributing virtual environments whose path contains ', `, $, ;, ( or ), and inspect the generated activation script before sourcing one you did not create.
Impact
The generated activate (bash/zsh) and activate.fish scripts interpolate a shlex.quote-ed value into a position that quotes it a second time. The extra quotes terminate the quoted run early and leave part of the value parsed as shell code, so a path containing shell metacharacters runs commands when a user sources the activation script.
activate is affected through the virtual environment's own path, on the branch that reports a relocated environment:
echo "Virtual environment directory __VIRTUAL_ENV__ does not exist!" >&2
For a destination named x'$(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.
Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.
CVE-2026-102925 has a CVSS score of 7.8 (High). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (21.7.13); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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
Frequently Asked Questions
- What is CVE-2026-102925? CVE-2026-102925 is a high-severity OS command injection vulnerability in virtualenv (pip), affecting versions <= 21.7.12. It is fixed in 21.7.13. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
- How severe is CVE-2026-102925? CVE-2026-102925 has a CVSS score of 7.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of virtualenv are affected by CVE-2026-102925? virtualenv (pip) versions <= 21.7.12 is affected.
- Is there a fix for CVE-2026-102925? Yes. CVE-2026-102925 is fixed in 21.7.13. Upgrade to this version or later.
- Is CVE-2026-102925 exploitable, and should I be worried? Whether CVE-2026-102925 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-102925 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-102925? Upgrade
virtualenvto 21.7.13 or later.