CVE-2026-55378
JS Recon: Command injection in PR Branch Checker workflow via untrusted pull request context values
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.
INFO
Published Date :
Aug. 28, 2026, 8:18 p.m.
Last Modified :
Aug. 28, 2026, 8:18 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-55378
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update JS Recon to version 1.3.1-beta.2.
- Review workflow file for untrusted input injection.
- Sanitize branch and fork names before use.
- Limit permissions of GITHUB_TOKEN.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55378.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55378 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55378
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55378 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55378 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Aug. 28, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-78 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55378.json">CVE-2026-55378</a> Added Reference https://github.com/js-recon/js-recon/commit/447876c4bfa9ec5bc98cbc65d7a3e5f889412491 Added Reference https://github.com/js-recon/js-recon/pull/121 Added Reference https://github.com/js-recon/js-recon/releases/tag/v1.3.1-beta.2 Added Reference https://github.com/js-recon/js-recon/security/advisories/GHSA-w9cj-mg3x-qjm4