CVE-2026-55378

CRITICALPre-NVD 9.39.3—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6%, top 54% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
9.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.3
EG Score
9.3(medium)
EG Risk
47(Track)
EG Risk 47/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity93% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
46%
KEV
Not listed

Published

August 28, 2026

Last Modified

August 28, 2026

Advisory Details (4)

Auto-updated Aug 29, 2026
Patch available. Sources: github_commit, github_pr, github_release, github.
github Patch Available

Command injection in PR Branch Checker workflow via untrusted pull request context values · Advisory · js-recon/js-recon · GitHub

https://github.com/js-recon/js-recon/security/advisories/GHSA-w9cj-mg3x-qjm4
github_release Patch Available

v1.3.1-beta.2

Patch available: js-recon/js-recon v1.3.1-beta.2 (pre-release)

https://github.com/js-recon/js-recon/releases/tag/v1.3.1-beta.2
github_pr Patch Available

v1.3.1-beta.2

Patch available: js-recon/js-recon v1.3.1-beta.2 (PR #121 merged 2026-06-12)

https://github.com/js-recon/js-recon/pull/121
github_commit Patch Available

commit 447876c4bfa9 (js-recon/js-recon)

Patch available: js-recon/js-recon v1.3.1-beta.2 (contains commit 447876c4bfa9)

https://github.com/js-recon/js-recon/commit/447876c4bfa9ec5bc98cbc65d7a3e5f889412491

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 5× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 02:23 UTCEG score recompute
  2. 2026-08-30 01:22 UTCEPSS rescore
  3. 2026-08-28 20:24 UTCEG score recompute
  4. 2026-08-28 19:38 UTCEG score recompute
  5. 2026-08-28 19:36 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55378?
CVE-2026-55378 is a critical vulnerability published on August 28, 2026. 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/prchecker.yml places github.headref and github.event.pullrequest.head.repo.fullname into BRANCHNAME and SOURCEREPO and interpolates those untrusted values…
When was CVE-2026-55378 disclosed?
CVE-2026-55378 was first published in the National Vulnerability Database on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55378 actively exploited?
CVE-2026-55378 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 54.0% of all scored CVEs.
What is the CVSS score of CVE-2026-55378?
CVE-2026-55378 has a CVSS v3 base score of 9.3 (NVD).
How do I remediate CVE-2026-55378?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55378, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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