What’s Vulnerable › Vulnerabilities

CVE-2026-44723: Vowpal Wabbit: Shell injection via crafted PR title in python_checks.yml allows arbitrary command execution on CI runner

• Severity: critical (CVSS 9.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-26 · updated 2026-07-24
• Weakness: CWE-78

Description

Vowpal Wabbit is a machine learning system. The workflow .github/workflows/python_checks.yml embeds ${{ github.event.pull_request.title }} directly inside double-quoted bash strings in four separate steps across four jobs, each passing it as a CLI argument to the Python test script run_tests_model_gen_and_load.py. The shell interprets the expanded string before invoking Python, allowing an attacker to break out of the quotes and execute arbitrary commands on the runner. The pull_request trigger fires on PRs targeting any branch (branches: ['*']), with no additional access gate. This vulnerability is fixed by the 998e390e80a7e8192d7849b7784bc113dbd190ad commit.

Affected products

• VowpalWabbit vowpal_wabbit: before 2026-05-04 — fixed in 2026-05-04

How to fix

Upgrade to a fixed version: VowpalWabbit vowpal_wabbit 2026-05-04. Check the vendor advisory for mitigations.

References

• https://github.com/VowpalWabbit/vowpal_wabbit/commit/998e390e80a7e8192d7849b7784bc113dbd190ad
• https://github.com/VowpalWabbit/vowpal_wabbit/security/advisories/GHSA-cg2g-xgg7-3xxq
• https://github.com/VowpalWabbit/vowpal_wabbit/security/advisories/GHSA-cg2g-xgg7-3xxq

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