# CVE-2026-113776: python3.13-virtualenv: virtualenv is a tool for creating isolated virtual python environments

CVE-2026-113776 is fixed in 2 products on 1 platform, first by ALAS2023-2026-3409, released November 10, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-113776
- Priority: High
- CVSS: n/a (important)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 9, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python3-virtualenv amzn 2023 | 20.4.0-3.amzn2023.0.6 | [ALAS2023-2026-3409](https://patchblox.com/security/data/fix/linux/alas2023-2026-3409.md) | Nov 10, 2026 |
| Linux | python3.13-virtualenv amzn 2023 | 20.21.1-1.amzn2023.0.5 | [ALAS2023-2026-3410](https://patchblox.com/security/data/fix/linux/alas2023-2026-3410.md) | Nov 10, 2026 |

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Data as of 2026-11-11T13:47:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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