virtualenv is a tool for creating isolated virtual python environments. Prior to 21.13.0, the bash activate script that zsh also sources leaves the environment name unescaped; from 21.13.0 until 21.14.4, it escapes backslashes, dollar signs, and backticks only when BASH_VERSION is set, so zsh receives the raw value. The script assigns that value to PS1. In zsh with PROMPT_SUBST, an attacker-influenced environment directory, --prompt, or VIRTUALENV_PROMPT value containing command, parameter, or arithmetic expansion syntax can therefore execute commands in the user's shell each time the prompt is drawn. A percent sign is separately interpreted as a zsh prompt escape but does not by itself execute commands. Plain zsh with PROMPT_SUBST disabled and bash are not affected by this mechanism. This issue is fixed in version 21.14.4.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-116",
"CWE-78"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/113xxx/CVE-2026-113726.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "21.14.4"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "5b915367da82bd024b2a0d28d2f98007034b4aa2"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "21.14.4",
"range": [
{
"fixed": "6657c5876b2185fd3feb77c1f03ec58246321c36"
}
],
"source": "REFERENCES_TAG"
}
]
}