CVE-2026-55158 is a critical-severity (CVSS 9.1) vulnerability in wktk/conflibot. O3 Security confirms whether CVE-2026-55158 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
conflibot vulnerable to command injection via crafted pull request branch names under pull_request_target
Real-World Exposure
wktk/conflibotReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects GitHub Actions packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Versions of conflibot before 1.2.1 build git commands by string interpolation and run them through a shell. Several of the interpolated values are pull request branch names (head.ref), which are attacker-controlled: anyone can open a pull request (including from a fork) whose head branch name contains shell metacharacters such as `, $( ), ;, |, or &.
The recommended workflow runs conflibot on the pull_request_target event, where the job has access to the base repository's secrets and a write-scoped GITHUB_TOKEN. As a result, a crafted branch name causes arbitrary command execution on the runner with that write token in the environment, allowing an attacker to exfiltrate secrets and the token, push to the repository, or otherwise abuse the token's permissions. No special privileges and no maintainer interaction are required — the action runs automatically when the pull request is opened.
Affected configurations
Any workflow using wktk/conflibot at a version earlier than 1.2.1. The risk is highest under pull_request_target (the documented configuration), because that is where the write token and secrets are exposed to attacker-influenced refs.
Patches
Fixed in 1.2.1 and 2.0.0. All git invocations now use argument arrays via execFile/spawn instead of a shell, so branch names can no longer be interpreted as shell syntax, and pull requests are referenced by number through refs/pull/<n>/head rather than by branch name.
Workarounds
There is no configuration-only workaround for affected versions. Upgrade to wktk/conflibot@v2. On GitHub-hosted runners this is a drop-in upgrade; self-hosted runners additionally need Node.js 24 support and git 2.38 or later.
Resources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | wktk/conflibot | all versions | 1.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wktk/conflibot. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update wktk/conflibot to 1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55158 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-55158 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-55158. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-55158 in your dependencies?
O3 detects CVE-2026-55158 across GitHub Actions dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.