Detections
Analytics
Amazon Linux 2023 : python3-virtualenv (ALAS2023-2026-3409)
high Nessus Plugin ID 377956
Synopsis
The remote Amazon Linux 2023 host is missing a security update.Description
It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3409 advisory.virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the stdlib venv creator reads generated pyvenv.cfg with str.splitlines() and merges parsed keys over virtualenv's selected configuration. An untrusted caller who influences the destination pathname can include a line-boundary character such as U+2028 to inject keys including home and include-system-site-packages, causing path data to change configuration structure before final output. Setting include-system-site-packages to true weakens environment isolation, while an altered home can change which standard-library files the interpreter loads if the attacker also controls that location. The builtin creator does not use this readback path. This issue is fixed in version 21.14.9. (CVE-2026-113715)
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, virtualenv's ScriptMakerCustom and pip pass an incompletely quoted interpreter path to distlib ScriptMaker when generating POSIX console scripts. When the path contains a space or produces a shebang longer than 127 bytes, distlib emits a /bin/sh wrapper whose double-quoted interpreter path still expands command substitutions and backticks. An attacker who influences the environment destination can therefore execute commands with the user's privileges when the user later runs a generated launcher; environment creation and activation do not trigger the command. Existing launchers are not repaired by upgrading virtualenv alone and must be regenerated, while a later independent pip installation or upgrade can reintroduce an affected launcher because pip's vendored distlib is unchanged. The virtualenv fix is released in version 21.14.9. (CVE-2026-113722)
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, caller-supplied prompt text can become executable syntax in the bash activation prompt. An attacker must influence the value passed to virtualenv, and a user must subsequently activate the environment and draw the prompt.
This vulnerability is fixed in 21.14.9. (CVE-2026-113723)
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.7, the bash activate script escapes the environment name for only one of the two passes bash makes over PS1, so a backslash in the name undoes the escaping and a name containing \$(...) runs as commands in the user's shell each time bash draws the prompt. This issue is fixed in version 21.14.7. (CVE-2026-113725)
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.
(CVE-2026-113726)
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.2, FishActivator inherits ViaTemplateActivator.quote(), which uses POSIX shlex.quote() even though fish interprets backslashes and single quotes differently. An attacker-influenced environment path, --prompt, or VIRTUALENV_PROMPT value containing a backslash before a quote can therefore terminate the generated fish literal and execute command substitution when the user sources activate.fish. This issue is fixed in version 21.14.2. (CVE-2026-113732)
virtualenv is a tool for creating isolated virtual python environments. From 20.26.6 until 21.14.2, ViaTemplateActivator.instantiate_template() replaces placeholders one key at a time across the complete activation template, so trigger names such as __VIRTUAL_NAME__, __VIRTUAL_ENV__, or __VIRTUAL_PROMPT__ inside an already substituted and quoted environment path or prompt can be replaced during a later pass.
The later value's quoting can close the earlier literal and execute the remaining path when a user activates the environment through bash, fish, xonsh, or activate_this.py. The distinct csh prompt-display token __VIRTUAL_PROMPT_DISPLAY_TCSH__ can instead break the generated script without establishing command execution. The attacker must influence the destination path or --prompt, and a value without a relevant placeholder name does not trigger this mechanism. This issue is fixed in version 21.14.2.
(CVE-2026-113776)
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. (CVE-2026-115586)
Tenable has extracted the preceding description block directly from the tested product security advisory.
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
Run 'dnf update python-virtualenv --releasever 2023.12.20261109' or or 'dnf update --advisory ALAS2023-2026-3409 --releasever 2023.12.20261109' to update your system.See Also
https://alas.aws.amazon.com//AL2023/ALAS2023-2026-3409.html
https://alas.aws.amazon.com/faqs.html
https://explore.alas.aws.amazon.com/CVE-2026-113715.html
https://explore.alas.aws.amazon.com/CVE-2026-113722.html
https://explore.alas.aws.amazon.com/CVE-2026-113723.html
https://explore.alas.aws.amazon.com/CVE-2026-113725.html
https://explore.alas.aws.amazon.com/CVE-2026-113726.html
https://explore.alas.aws.amazon.com/CVE-2026-113732.html
Plugin Details
Severity: High
ID: 377956
File Name: al2023_ALAS2023-2026-3409.nasl
Version: 1.1
Type: Local
Agent: unix
Published: 11/9/2026
Updated: 11/9/2026
Supported Sensors: Nessus Agent, Continuous Assessment, Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 5
Percentile: 92.81
CVSS v2
Risk Factor: High
Base Score: 7.2
Temporal Score: 5.3
Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2026-113776
CVSS v3
Risk Factor: High
Base Score: 7.8
Temporal Score: 6.8
Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
CVSS v4
Risk Factor: High
Base Score: 7.1
Threat Score: 4
Threat Vector: CVSS:4.0/E:U
Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score Source: CVE-2026-115586
Vulnerability Information
CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:python3-virtualenv
Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 11/9/2026
Vulnerability Publication Date: 10/20/2026
Reference Information
CVE: CVE-2026-113715, CVE-2026-113722, CVE-2026-113723, CVE-2026-113725, CVE-2026-113726, CVE-2026-113732, CVE-2026-113776, CVE-2026-115586