OS Command Injection in virtualenv (CVE-2026-102937)
Summary
OS command injection in virtualenv (CVE-2026-102937). Risk of unauthorized operations or information disclosure. Exploitable via VIRTUALENV_PROMPT. Mitigation: upgrade to 21.7.12 or later.
Original description
The description as published by the source.
BatchActivator.quote() returned its input unchanged, the only activator with
no escaping at all. --prompt, the VIRTUALENV_PROMPT environment variable,
and the config file all set the prompt, and activate.bat writes it straight
into @set "VAR=value". A prompt containing a double quote closes that string
early, and whatever follows runs as live cmd.exe syntax. For example, a venv
created with --prompt 'x" & calc & "' runs calc the moment someone runs
activate.bat.
Anyone who templates a prompt from untrusted input (a CI job using a branch
name, a wrapper script deriving an environment name from user input) hands an
attacker code execution in the shell of anyone who activates the resulting venv
on Windows.
Fixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax
inside this construct.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-102937 has been found in virtualenv.
Attackers can target a specific entry point like VIRTUALENV_PROMPT over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade virtualenv to 21.7.12 or later.
If unsure, ask your IT team or search "virtualenv CVE-2026-102937" on the vendor's site.
CVE-2026-102937 (virtualenv) — CWE-78
Attack surface: VIRTUALENV_PROMPT / activate.bat / calc
Patched: 21.7.12 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
OS command injection (CWE-78) exists in virtualenv. Attackers reach the vulnerable code path via VIRTUALENV_PROMPT.
Check the vendor advisory for the affected versions of virtualenv. Attack surface: VIRTUALENV_PROMPT / activate.bat / calc.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 21.7.12.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'virtualenv' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'virtualenv' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
virtualenvを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade virtualenv to 21.7.12ステージング環境で 21.7.12 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-102937 python-virtualenv
- Ubuntu UBUNTU-CVE-2026-102937 python-virtualenv
References
- advisory nvd.nist.gov
- package github.com
- package pypi.org
- patch github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com