Vowpal WabbitApplication · Vowpalwabbit

CVE-2026-44723

CRITICAL · 9.9 CVSS v3.1 Published 2026-05-26
Fix available
A fix is available. Upgrade to 2026-05-04 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The GitHub Actions workflow python_checks.yml directly interpolates the pull request title (${{ github.event.pull_request.title }}) into double-quoted bash strings passed as CLI arguments to a Python test script. Because the title is expanded by the shell before Python execution, an attacker can craft a malicious PR title containing shell metacharacters to break out of the quotes and execute arbitrary commands on the runner.

MitigationSanitize the pull request title using environment variables or escape shell metacharacters before embedding it in bash strings, or pass the title to Python via environment variables rather than shell command interpolation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Vowpal WabbitApplication
Affected:< 2026-05-04

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if python_checks.yml workflow exists
    Locate the .github/workflows/python_checks.yml file in the repository or download it from the remote
    Affected if The file does not exist - the vulnerability does not apply to this environment
  2. Inspect workflow for vulnerable PR title usage
    Examine the workflow YAML content for patterns where ${{ github.event.pull_request.title }} is passed directly as CLI arguments to Python scripts within bash strings
    Affected if The PR title variable is directly embedded into shell command strings without sanitization
  3. Check for input sanitization implementation
    Look for evidence of proper input handling such as environment variable usage, input validation libraries, or the fix commit 998e390e in the repository history
    Affected if No sanitization is implemented and the vulnerable pattern is present
  4. Verify version is before the fix date
    Check the installed Vowpal Wabbit version or the repository commit date against the 2026-05-04 release date
    Affected if The version or commit predates 2026-05-04 and contains the vulnerable workflow

Affected if the repository contains the python_checks.yml workflow with direct PR title injection into shell strings and the version/commit predates the 2026-05-04 fix.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2026-05-04 or later
Fixed in 2026-05-04
Vendor patch github.com →
Interim mitigation

Sanitize the pull request title using environment variables or escape shell metacharacters before embedding it in bash strings, or pass the title to Python via environment variables rather than shell command interpolation.

Recommended fix High confidence

Vowpal Wabbit >= 2026-05-04

  1. Review the vulnerable .github/workflows/python_checks.yml file in the repository
  2. Locate the four steps where ${{ github.event.pull_request.title }} is used within double-quoted bash strings
  3. Apply the fix from commit 998e390e80a7e8192d7849b7784bc113dbd190ad which properly escapes or sanitizes the PR title before passing it to Python
  4. Verify that pull_request triggers are appropriately scoped (not using branches: ['*'] if possible)
  5. After applying the fix, test the workflow with a benign PR title to confirm the pipeline still functions correctly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Vowpal Wabbit Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44723 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data