CVE-2026-46420

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 1.5%, top 27% 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, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 9.8Exploit: None knownExposed: 0

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

setup-php is a GitHub action to set up PHP with extensions, php.ini configuration, coverage drivers, and tools. From 2.25.0 prior to 2.37.1, shivammathur/setup-php resolves the PHP version from repository-controlled files such as .php-version, composer.lock through platform-overrides.php, and composer.json through config.platform.php, and insufficiently constrains those values before incorporating them into generated shell or PowerShell setup scripts, allowing command injection on a GitHub Actions runner when workflows such as pull_request_target check out attacker-controlled contents before invoking setup-php. This issue is fixed in version 2.37.1.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity98% × 45%
Exploitation2% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
73%
KEV
Not listed

Published

May 20, 2026

Last Modified

August 18, 2026

Advisory Details (3)

Auto-updated Sep 1, 2026
Patch available. Sources: github_commit, github_release, github.
github Patch Available

Command Injection in Repository-Derived PHP Version Resolution · Advisory · shivammathur/setup-php · GitHub

https://github.com/shivammathur/setup-php/security/advisories/GHSA-pqwm-q9pv-ph8r
github_release Patch Available

2.37.1

Patch available: shivammathur/setup-php 2.37.1

https://github.com/shivammathur/setup-php/releases/tag/2.37.1
github_commit Patch Available

commit eeef37e059fb (shivammathur/setup-php)

Patch available: shivammathur/setup-php 2.37.1 (contains commit eeef37e059fb)

https://github.com/shivammathur/setup-php/commit/eeef37e059fb5368a5bc8ed8ce45ff54bd39b80b

Vendor Advisories for CVE-2026-46420(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 39× 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. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 14:12 UTCEPSS rescore
  3. 2026-09-01 13:54 UTCEPSS rescore
  4. 2026-08-30 19:17 UTCEPSS rescore
  5. 2026-08-30 01:22 UTCEPSS rescore
  6. 2026-08-28 21:41 UTCEPSS rescore
  7. 2026-08-27 14:25 UTCEPSS rescore
  8. 2026-08-26 14:46 UTCEPSS rescore
  9. 2026-08-25 13:49 UTCEPSS rescore
  10. 2026-08-23 16:54 UTCEG score recompute
  11. 2026-08-23 00:19 UTCEPSS rescore
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-21 22:54 UTCEG score recompute
  14. 2026-08-20 22:55 UTCEPSS rescore
  15. 2026-08-20 18:55 UTCEG score recompute
  16. 2026-08-19 17:04 UTCEPSS rescore
  17. 2026-08-18 16:58 UTCEG score recompute▲ 4.20
  18. 2026-08-18 15:59 UTCNVD updateCVSS v3 → 9.8 · severity → CRITICAL
  19. 2026-08-18 13:48 UTCEPSS rescore
  20. 2026-08-17 13:47 UTCEPSS rescore
  21. 2026-08-17 09:53 UTCEG score recompute
  22. 2026-08-16 14:56 UTCEPSS rescore
  23. 2026-08-16 03:29 UTCEG score recompute
  24. 2026-08-16 02:14 UTCEPSS rescore
  25. 2026-08-15 01:30 UTCEPSS rescore
Show 42 more
  1. 2026-08-14 02:01 UTCEG score recompute
  2. 2026-08-13 22:00 UTCEPSS rescore
  3. 2026-08-12 22:27 UTCEG score recompute
  4. 2026-08-12 13:51 UTCEPSS rescore
  5. 2026-08-11 23:31 UTCEG score recompute
  6. 2026-08-11 00:35 UTCEG score recompute
  7. 2026-08-11 00:00 UTCEPSS rescore
  8. 2026-08-10 00:27 UTCEG score recompute
  9. 2026-08-09 13:46 UTCEPSS rescore
  10. 2026-08-09 01:32 UTCEG score recompute
  11. 2026-08-08 16:37 UTCEPSS rescore
  12. 2026-08-07 19:08 UTCEG score recompute
  13. 2026-08-06 20:12 UTCEG score recompute
  14. 2026-08-06 13:47 UTCEPSS rescore
  15. 2026-08-05 21:16 UTCEG score recompute
  16. 2026-08-05 19:17 UTCEPSS rescore
  17. 2026-08-04 15:10 UTCEPSS rescore
  18. 2026-08-04 10:39 UTCEPSS rescore
  19. 2026-08-03 16:54 UTCEG score recompute
  20. 2026-08-03 10:36 UTCEPSS rescore
  21. 2026-08-02 16:38 UTCEG score recompute
  22. 2026-08-02 02:27 UTCEPSS rescore
  23. 2026-08-01 17:42 UTCEG score recompute
  24. 2026-08-01 04:16 UTCEPSS rescore
  25. 2026-07-30 16:28 UTCEPSS rescore
  26. 2026-07-30 01:30 UTCEPSS rescore
  27. 2026-07-28 15:36 UTCEPSS rescore
  28. 2026-07-27 14:13 UTCEPSS rescore
  29. 2026-07-26 08:14 UTCEG score recompute
  30. 2026-07-25 14:18 UTCEPSS rescore
  31. 2026-07-24 14:17 UTCEPSS rescore
  32. 2026-07-23 14:18 UTCEPSS rescore
  33. 2026-07-23 03:17 UTCEG score recompute
  34. 2026-07-22 14:08 UTCEPSS rescore
  35. 2026-07-21 15:24 UTCEPSS rescore
  36. 2026-07-20 17:08 UTCEPSS rescore
  37. 2026-07-19 14:31 UTCEPSS rescore
  38. 2026-07-19 02:29 UTCEPSS rescore
  39. 2026-06-14 23:18 UTCEPSS rescore
  40. 2026-06-13 23:00 UTCEPSS rescore
  41. 2026-06-12 23:12 UTCEPSS rescore
  42. 2026-05-24 06:12 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-46420?
CVE-2026-46420 is a critical vulnerability published on May 20, 2026. setup-php is a GitHub action to set up PHP with extensions, php.ini configuration, coverage drivers, and tools. From 2.25.0 prior to 2.37.1, shivammathur/setup-php resolves the PHP version from repository-controlled files such as .php-version, composer.lock through platform-overrides.php, and…
When was CVE-2026-46420 disclosed?
CVE-2026-46420 was first published in the National Vulnerability Database on May 20, 2026, with the most recent update on August 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-46420 actively exploited?
CVE-2026-46420 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 26.8% of all scored CVEs.
What is the CVSS score of CVE-2026-46420?
CVE-2026-46420 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-46420?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-46420, 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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