How severe is GHSA-8rjx-v5ww-45pp?

GHSA-8rjx-v5ww-45pp has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-8rjx-v5ww-45pp?

GHSA-8rjx-v5ww-45pp affects the following packages: virtualenv (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-8rjx-v5ww-45pp?

Update virtualenv to 21.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8rjx-v5ww-45pp is resolved across your whole dependency graph.

How do I detect GHSA-8rjx-v5ww-45pp in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for virtualenv, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-8rjx-v5ww-45pp if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is GHSA-8rjx-v5ww-45pp actively exploited in the wild?

No public exploit code has been indexed for GHSA-8rjx-v5ww-45pp yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-8rjx-v5ww-45pp?

GHSA-8rjx-v5ww-45pp has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 15th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-8rjx-v5ww-45pp?

GHSA-8rjx-v5ww-45pp is classified as OS Command Injection (CWE-78), Code Injection (CWE-94). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-8rjx-v5ww-45pp published, and has it been updated?

GHSA-8rjx-v5ww-45pp was published on October 21, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

HIGH severity

virtualenv activation scripts run code from a path that contains a placeholder nameGHSA-8rjx-v5ww-45pp

HIGHFix: pypa/virtualenv@602b266

GHSA-8rjx-v5ww-45pp is a high-severity (CVSS 7.8) OS Command Injection vulnerability in virtualenv. A fix is available for virtualenv — see the affected versions and patch details below.

Also known asCVE-2026-113776

Published

Oct 21, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs15th percentile — riskier than 15% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-8rjx-v5ww-45pp by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐍virtualenv

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

ViaTemplateActivator.instantiate_template replaces the placeholders in an activation template one key at a time, each across the whole text. When a value that it already substituted and quoted contains the name of a later placeholder, the later pass rewrites that name inside the quoted literal. The inserted value brings its own quotes, which close the outer literal, and the rest of the path runs as code when a user activates the environment.

__VIRTUAL_NAME__ holds the environment's directory name, so a destination such as A__VIRTUAL_NAME__B/x'$(touch PWNED)'y is enough. In the default activate for bash, the VIRTUAL_ENV line renders as:

VIRTUAL_ENV='/tmp/t/A'x'"'"'$(touch PWNED)'"'"'y'B/x'"'"'$(touch PWNED)'"'"'y'

Sourcing that script runs touch PWNED. The same payload in a path without the placeholder name runs nothing. activate.fish runs the command the same way, and the reporter also showed Python code execution through activate.xsh and bin/activate_this.py. In activate.csh, a directory named after a prompt display placeholder, such as __VIRTUAL_PROMPT_DISPLAY_TCSH__, breaks the script with Unmatched '''.

No change to quote() can stop this, because the rewrite happens after quote() ran; it defeats shlex.quote and repr() alike.

An attacker needs to influence the destination path or --prompt: a CI job or wrapper tool that builds the path from a branch or project name, or a directory in a cloned repository or unpacked archive.

The bug affects versions 20.26.6 through 21.14.1. Version 20.26.6 first quoted template values (#2768) and introduced the per-key loop.

Patches

Fixed in 21.14.2. Activation scripts now keep a placeholder name in the environment's path or prompt as plain text, and activating the example above runs nothing. Fix: https://github.com/pypa/virtualenv/commit/602b26623a724827ff171bf11fef4ad186d01f74

Workarounds

Do not create an environment whose path or --prompt contains a placeholder name such as __VIRTUAL_NAME__, __VIRTUAL_ENV__ or __VIRTUAL_PROMPT__, and inspect the generated activation script before you source one you did not create.

Credits

Kevin Stubbings (@Kwstubbs) of GitHub Security Lab reported this issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`virtualenv`	≥ 20.26.6&&< 21.14.2	21.14.2`pip install --upgrade 'virtualenv==21.14.2'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for virtualenv, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update virtualenv to 21.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8rjx-v5ww-45pp is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

### Impact `ViaTemplateActivator.instantiate_template` replaces the placeholders in an activation template one key at a time, each across the whole text. When a value that it already substituted and quoted contains the name of a later placeholder, the later pass rewrites that name inside the quoted literal. The inserted value brings its own quotes, which close the outer literal, and the rest of the path runs as code when a user activates the environment. `__VIRTUAL_NAME__` holds the environment's directory name, so a destination such as `A__VIRTUAL_NAME__B/x'$(touch PWNED)'y` is enough. In t