CVE-2026-55378

CRITICALPre-NVD 9.39.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (57th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
9.3EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 9.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
9.3CRITICALmedium confidence
EG Risk
42
EG Risk 42/100

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 (value × EchelonGraph’s weight)
Severity93% × 45%
The EG Score, 9.3 of 10.
Exploitation0.9% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.8%
EPSS %ILE
57th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 28, 2026

Last Modified

September 9, 2026

Advisory Details (4)

Auto-updated Oct 3, 2026
Patch available. Sources: github_commit, github_pr, github_release, github.
GitHub advisoryMentions a patch (unverified)

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 pull request 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 16× in last 7d / 55× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-14 01:56 UTCEG score recompute
  2. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  3. 2026-10-12 22:12 UTCEG score recompute
  4. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  5. 2026-10-12 15:55 UTCEG score recompute
  6. 2026-10-11 19:39 UTCEG score recompute
  7. 2026-10-11 16:54 UTCEG score recompute
  8. 2026-10-11 14:17 UTCEG score recompute
  9. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  10. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  11. 2026-10-10 00:50 UTCEG score recompute
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  13. 2026-10-09 02:38 UTCEG score recompute
  14. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  15. 2026-10-08 00:50 UTCEG score recompute
  16. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  17. 2026-10-06 16:00 UTCEG score recompute
  18. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  19. 2026-10-05 17:43 UTCEG score recompute
  20. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  21. 2026-10-03 19:18 UTCEG score recompute
  22. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  23. 2026-10-02 19:51 UTCEG score recompute
  24. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  25. 2026-10-02 00:37 UTCEG score recompute
Show 63 more
  1. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  2. 2026-09-30 19:49 UTCEG score recompute
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  4. 2026-09-30 03:49 UTCEG score recompute
  5. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  6. 2026-09-29 01:23 UTCEG score recompute
  7. 2026-09-28 16:21 UTCEG score recompute
  8. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  9. 2026-09-27 14:23 UTCEG score recompute
  10. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  11. 2026-09-26 20:24 UTCEG score recompute
  12. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  13. 2026-09-26 08:04 UTCEG score recompute
  14. 2026-09-24 17:11 UTCEG score recompute
  15. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  16. 2026-09-23 19:52 UTCEG score recompute
  17. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  18. 2026-09-22 18:17 UTCEG score recompute
  19. 2026-09-21 23:41 UTCEG score recompute
  20. 2026-09-19 16:01 UTCEG score recompute
  21. 2026-09-18 22:34 UTCEG score recompute
  22. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  23. 2026-09-17 20:50 UTCEG score recompute
  24. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  25. 2026-09-16 18:58 UTCEG score recompute
  26. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  27. 2026-09-16 09:11 UTCEG score recompute
  28. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  29. 2026-09-15 05:46 UTCEG score recompute
  30. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  31. 2026-09-13 19:20 UTCEG score recompute
  32. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  33. 2026-09-12 17:44 UTCEG score recompute
  34. 2026-09-11 16:09 UTCEG score recompute
  35. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  36. 2026-09-11 11:48 UTCEG score recompute
  37. 2026-09-10 10:01 UTCEG score recompute
  38. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  39. 2026-09-09 00:27 UTCEG score recompute
  40. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  41. 2026-09-07 19:18 UTCEG score recompute
  42. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-09-06 15:32 UTCEG score recompute
  44. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  45. 2026-09-05 18:09 UTCEG score recompute
  46. 2026-09-04 16:16 UTCEG score recompute
  47. 2026-09-04 07:45 UTCEG score recompute
  48. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  49. 2026-09-02 17:08 UTCEG score recompute
  50. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  51. 2026-09-01 15:15 UTCEG score recompute
  52. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  53. 2026-09-01 06:40 UTCEG score recompute
  54. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  55. 2026-09-01 02:23 UTCEG score recompute
  56. 2026-09-01 02:10 UTCEG score recompute
  57. 2026-08-30 19:26 UTCEG score recompute
  58. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  59. 2026-08-30 02:23 UTCEG score recompute
  60. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  61. 2026-08-28 20:24 UTCEG score recompute
  62. 2026-08-28 19:38 UTCEG score recomputeFirst assessed: 9.3 CRITICAL
  63. 2026-08-28 19:36 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-55378?
CVE-2026-55378 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-55378 published?
The CVE record for CVE-2026-55378 was published on August 28, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-55378 actively exploited?
CVE-2026-55378 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (57th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55378?
CVE-2026-55378 has a CVSS base score of 9.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55378?
A fix for CVE-2026-55378 is available: update to the fixed version the vendor names in its advisory.

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