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Vulnerability · Published Aug 28, 2026 · Assigned by GitHub_M

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

Critical 9.3

In plain English

A critical-severity OS command injection in js-recon from shriyanss. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 58% of all known vulnerabilities).

Severity (CVSS 4.0)9.3Critical
Exploit odds (30 days)0.8%top 41.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
shriyanss js-recon >= 1.2.1-beta.1, < 1.3.1-beta.2

Weakness: CWE-78 · 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

References