CVE-2026-44723: Vowpalwabbit Vowpal Wabbit

Critical severity, CVSS 9.9. EPSS: 0.6% chance of exploitation in the next 30 days.

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)

Published 2026-05-26. Last modified 2026-07-24.