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
References3
- github.com/VowpalWabbit/vowpal_wabbit/security/advisories/GHSA-… ExploitMitigationVendor Advisory
- github.com/VowpalWabbit/vowpal_wabbit/security/advisories/GHSA-… ExploitMitigationVendor Advisory
- github.com/VowpalWabbit/vowpal_wabbit/commit/998e390e80a7e8192d… Patch
Metrics
- CVSS 3.1
-
9.9
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 41 · as of 14 November 2026
- CWE
- CWE-78CWE-1336
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.