CVE-2026-66399

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-27. the CNA's CVSS baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

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

phpMyFAQ before 4.1.6 contains a privilege escalation vulnerability in GroupController::updateMembers() that allows administrators with only group-management permissions to join privileged groups without verification of required rights. Attackers can add themselves to pre-existing groups holding user-management rights and immediately inherit those permissions to modify or delete user accounts.

CVSS v3
6.5
EG Score
6.5(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
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
14%
KEV
Not listed

Published

July 27, 2026

Last Modified

August 18, 2026

Advisory Details (2)

Auto-updated Jul 27, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

phpMyFAQ before 4.1.6 Privilege Escalation via Group Membership | Advisories | VulnCheck

https://www.vulncheck.com/advisories/phpmyfaq-before-privilege-escalation-via-group-membership
github Patch Available🟡 PoC Available

Privilege Escalation via Unrestricted Group-Membership Assignment in GroupController::updateMembers (Sibling Gap to GHSA-pg62-f8g4-4wqh) · Advisory · thorsten/phpMyFAQ · GitHub

https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-28cc-v39j-vr95

Vendor Advisories for CVE-2026-66399(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 13× in last 7d / 82× 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 01:22 UTCEPSS rescore
  2. 2026-08-29 23:52 UTCEG score recompute
  3. 2026-08-29 23:52 UTCGHSA enrichment
  4. 2026-08-28 21:42 UTCEPSS rescore
  5. 2026-08-28 01:42 UTCEG score recompute
  6. 2026-08-28 01:42 UTCGHSA enrichment
  7. 2026-08-27 02:41 UTCEG score recompute
  8. 2026-08-27 02:41 UTCGHSA enrichment
  9. 2026-08-26 14:47 UTCEPSS rescore
  10. 2026-08-26 03:40 UTCGHSA enrichment
  11. 2026-08-25 04:39 UTCEG score recompute
  12. 2026-08-25 04:39 UTCGHSA enrichment
  13. 2026-08-24 05:37 UTCGHSA enrichment
  14. 2026-08-23 06:36 UTCEG score recompute
  15. 2026-08-23 06:35 UTCGHSA enrichment
  16. 2026-08-23 00:19 UTCEPSS rescore
  17. 2026-08-22 07:35 UTCEG score recompute
  18. 2026-08-22 07:35 UTCGHSA enrichment
  19. 2026-08-21 23:49 UTCEPSS rescore
  20. 2026-08-21 08:33 UTCEG score recompute
  21. 2026-08-21 08:33 UTCGHSA enrichment
  22. 2026-08-20 22:56 UTCEPSS rescore
  23. 2026-08-20 09:32 UTCEG score recompute
  24. 2026-08-20 09:32 UTCGHSA enrichment
  25. 2026-08-19 17:04 UTCEPSS rescore
Show 72 more
  1. 2026-08-19 10:31 UTCEG score recompute
  2. 2026-08-19 10:31 UTCGHSA enrichment
  3. 2026-08-18 13:48 UTCEPSS rescore
  4. 2026-08-18 11:30 UTCEG score recompute
  5. 2026-08-18 11:30 UTCGHSA enrichment
  6. 2026-08-17 20:15 UTCEG score recompute
  7. 2026-08-17 20:15 UTCGHSA enrichment
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-16 21:10 UTCEG score recompute
  10. 2026-08-16 21:10 UTCGHSA enrichment
  11. 2026-08-16 14:56 UTCEPSS rescore
  12. 2026-08-15 22:09 UTCEG score recompute
  13. 2026-08-15 22:09 UTCGHSA enrichment
  14. 2026-08-15 01:30 UTCEPSS rescore
  15. 2026-08-14 23:08 UTCGHSA enrichment
  16. 2026-08-14 00:07 UTCEG score recompute
  17. 2026-08-14 00:07 UTCGHSA enrichment
  18. 2026-08-13 22:00 UTCEPSS rescore
  19. 2026-08-13 01:06 UTCEG score recompute
  20. 2026-08-13 01:06 UTCGHSA enrichment
  21. 2026-08-12 13:51 UTCEPSS rescore
  22. 2026-08-12 02:05 UTCEG score recompute
  23. 2026-08-12 02:05 UTCGHSA enrichment
  24. 2026-08-11 03:04 UTCEG score recompute
  25. 2026-08-11 03:04 UTCGHSA enrichment
  26. 2026-08-11 00:00 UTCEPSS rescore
  27. 2026-08-10 04:02 UTCEG score recompute
  28. 2026-08-10 04:02 UTCGHSA enrichment
  29. 2026-08-09 13:47 UTCEPSS rescore
  30. 2026-08-09 05:01 UTCEG score recompute
  31. 2026-08-09 05:01 UTCGHSA enrichment
  32. 2026-08-08 16:37 UTCEPSS rescore
  33. 2026-08-08 06:00 UTCEG score recompute
  34. 2026-08-08 06:00 UTCGHSA enrichment
  35. 2026-08-07 06:59 UTCEG score recompute
  36. 2026-08-07 06:59 UTCGHSA enrichment
  37. 2026-08-06 13:47 UTCEPSS rescore
  38. 2026-08-06 07:58 UTCEG score recompute
  39. 2026-08-06 07:58 UTCGHSA enrichment
  40. 2026-08-05 19:17 UTCEPSS rescore
  41. 2026-08-05 19:17 UTCEPSS rescore
  42. 2026-08-05 08:57 UTCEG score recompute
  43. 2026-08-05 08:57 UTCGHSA enrichment
  44. 2026-08-04 15:10 UTCEPSS rescore
  45. 2026-08-04 10:39 UTCEPSS rescore
  46. 2026-08-04 09:57 UTCGHSA enrichment
  47. 2026-08-03 10:55 UTCEG score recompute
  48. 2026-08-03 10:55 UTCGHSA enrichment
  49. 2026-08-03 10:36 UTCEPSS rescore
  50. 2026-08-02 11:46 UTCEG score recompute
  51. 2026-08-02 11:46 UTCGHSA enrichment
  52. 2026-08-02 02:27 UTCEPSS rescore
  53. 2026-08-01 12:45 UTCEG score recompute
  54. 2026-08-01 12:45 UTCGHSA enrichment
  55. 2026-08-01 04:16 UTCEPSS rescore
  56. 2026-07-31 13:42 UTCEG score recompute
  57. 2026-07-31 13:42 UTCGHSA enrichment
  58. 2026-07-30 16:28 UTCEPSS rescore
  59. 2026-07-30 14:40 UTCEG score recompute
  60. 2026-07-30 14:40 UTCGHSA enrichment
  61. 2026-07-30 01:30 UTCEPSS rescore
  62. 2026-07-29 15:32 UTCGHSA enrichment
  63. 2026-07-28 16:30 UTCEG score recompute
  64. 2026-07-28 16:30 UTCGHSA enrichment
  65. 2026-07-28 15:37 UTCEG score recompute
  66. 2026-07-28 15:37 UTCEPSS rescore
  67. 2026-07-28 15:37 UTCGHSA enrichment
  68. 2026-07-28 01:30 UTCEG score recompute
  69. 2026-07-28 01:30 UTCGHSA enrichment
  70. 2026-07-27 16:24 UTCEG score recompute
  71. 2026-07-27 16:16 UTCEG score recompute
  72. 2026-07-27 16:16 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66399?
CVE-2026-66399 is a medium vulnerability published on July 27, 2026. phpMyFAQ before 4.1.6 contains a privilege escalation vulnerability in GroupController::updateMembers() that allows administrators with only group-management permissions to join privileged groups without verification of required rights. Attackers can add themselves to pre-existing groups holding…
When was CVE-2026-66399 disclosed?
CVE-2026-66399 was first published in the National Vulnerability Database on July 27, 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-2026-66399 actively exploited?
CVE-2026-66399 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 86.3% of all scored CVEs.
What is the CVSS score of CVE-2026-66399?
CVE-2026-66399 has a CVSS v4.0 base score of 6.5 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-66399?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66399, 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.

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