pypa virtualenv up to 21.14.12 Activation Script bin/activate prompt code injection

Summaryinfo

A vulnerability categorized as problematic has been discovered in pypa virtualenv up to 21.14.12. The affected element is an unknown function of the file bin/activate of the component Activation Script. Such manipulation of the argument prompt leads to code injection. This vulnerability is traded as CVE-2026-115586. An attack has to be approached locally. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in pypa virtualenv up to 21.14.12. It has been rated as problematic. Affected by this issue is an unknown functionality of the file bin/activate of the component Activation Script. The manipulation of the argument prompt with an unknown input leads to a code injection vulnerability. Using CWE to declare the problem leads to CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Impacted is confidentiality, integrity, and availability. CVE summarizes:

virtualenv is a tool for creating isolated virtual python environments. From 21.14.9 until 21.14.13, the bash bin/activate script can copy an attacker-controlled --prompt value into PS1 without escaping dollar signs or backticks when both promptvars and POSIX mode are disabled during activation. Re-enabling promptvars, running set -o posix, or starting an interactive child bash that inherits the exported PS1 can then expand command substitution in the stored VIRTUAL_ENV_PROMPT value and execute commands as the user who activates the environment. This issue is fixed in version 21.14.13.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-115586 since 10/23/2026. The exploitation is known to be easy. Local access is required to approach this attack. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1059 by the MITRE ATT&CK project.

Upgrading to version 21.14.13 eliminates this vulnerability.

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Productinfo

Vendor

• pypa

Name

• virtualenv

Version

• 21.14.0
• 21.14.1
• 21.14.2
• 21.14.3
• 21.14.4
• 21.14.5
• 21.14.6
• 21.14.7
• 21.14.8
• 21.14.9
• 21.14.10
• 21.14.11
• 21.14.12

Website

• Product: https://github.com/pypa/virtualenv/

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