CVE-2026-55378
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 this means for your business
- FIRST's prediction model gives it a 0.6% chance of attack attempts being seen in the next 30 days, ranking above 46% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- Not yet scored
- CVSS v4
- 9.3
- Weakness
- CWE-78
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-08-28
- Last modified
- 2026-09-09
- Sources
- NVD