CVE-2026-77991

CRITICALPre-NVD 9.49.4—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 65% 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
9.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.4Exploit: None knownExposed: 0

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

Joomla Extension - joomlaeventmanager.net - Privileged remote code execution in Joomla Event Manager < 5.0.1 - The administrator source model allows to write dangerous file type incl. PHP, leading to remote code execution.

CVSS v3
9.4
EG Score
9.4(medium)
EG Risk
42(Track)
EG Risk 42/100SSVC: 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
Severity94% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
35%
KEV
Not listed

Published

August 27, 2026

Last Modified

August 28, 2026

Advisory Details (1)

Auto-updated Sep 14, 2026
No patch confirmed yet.
generic

JEM - Joomla Event Manager

https://www.joomlaeventmanager.net/

Vendor Advisories for CVE-2026-77991(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 54× in last 7d / 200× 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.

Showing the most recent 100 of 200 total refreshes for this CVE.

  1. 2026-09-21 13:24 UTCGHSA enrichment
  2. 2026-09-21 09:28 UTCGHSA enrichment
  3. 2026-09-21 05:34 UTCGHSA enrichment
  4. 2026-09-21 01:38 UTCGHSA enrichment
  5. 2026-09-20 21:37 UTCEG score recompute
  6. 2026-09-20 21:37 UTCGHSA enrichment
  7. 2026-09-20 20:16 UTCEPSS rescore
  8. 2026-09-20 17:43 UTCGHSA enrichment
  9. 2026-09-20 13:45 UTCGHSA enrichment
  10. 2026-09-20 09:50 UTCGHSA enrichment
  11. 2026-09-20 05:56 UTCGHSA enrichment
  12. 2026-09-20 02:02 UTCGHSA enrichment
  13. 2026-09-19 22:08 UTCGHSA enrichment
  14. 2026-09-19 18:14 UTCEG score recompute
  15. 2026-09-19 18:14 UTCGHSA enrichment
  16. 2026-09-19 14:13 UTCGHSA enrichment
  17. 2026-09-19 10:02 UTCGHSA enrichment
  18. 2026-09-19 05:20 UTCGHSA enrichment
  19. 2026-09-19 01:26 UTCGHSA enrichment
  20. 2026-09-18 21:30 UTCEG score recompute
  21. 2026-09-18 21:30 UTCGHSA enrichment
  22. 2026-09-18 19:28 UTCEPSS rescore
  23. 2026-09-18 16:31 UTCGHSA enrichment
  24. 2026-09-18 12:31 UTCGHSA enrichment
  25. 2026-09-18 08:37 UTCGHSA enrichment
Show 75 more
  1. 2026-09-18 04:43 UTCGHSA enrichment
  2. 2026-09-18 00:49 UTCGHSA enrichment
  3. 2026-09-17 20:55 UTCEG score recompute
  4. 2026-09-17 20:55 UTCGHSA enrichment
  5. 2026-09-17 14:55 UTCGHSA enrichment
  6. 2026-09-17 11:01 UTCGHSA enrichment
  7. 2026-09-17 07:07 UTCGHSA enrichment
  8. 2026-09-17 03:12 UTCGHSA enrichment
  9. 2026-09-16 22:58 UTCGHSA enrichment
  10. 2026-09-16 19:04 UTCGHSA enrichment
  11. 2026-09-16 15:07 UTCEG score recompute
  12. 2026-09-16 15:07 UTCGHSA enrichment
  13. 2026-09-16 14:08 UTCEPSS rescore
  14. 2026-09-16 11:13 UTCGHSA enrichment
  15. 2026-09-16 07:19 UTCEG score recompute
  16. 2026-09-16 07:19 UTCGHSA enrichment
  17. 2026-09-16 05:15 UTCEPSS rescore
  18. 2026-09-16 03:25 UTCGHSA enrichment
  19. 2026-09-15 23:31 UTCGHSA enrichment
  20. 2026-09-15 19:04 UTCGHSA enrichment
  21. 2026-09-15 15:09 UTCGHSA enrichment
  22. 2026-09-15 11:08 UTCGHSA enrichment
  23. 2026-09-15 06:32 UTCEG score recompute
  24. 2026-09-15 06:32 UTCGHSA enrichment
  25. 2026-09-15 03:12 UTCEPSS rescore
  26. 2026-09-15 03:12 UTCEPSS rescore
  27. 2026-09-15 02:38 UTCGHSA enrichment
  28. 2026-09-14 22:44 UTCGHSA enrichment
  29. 2026-09-14 18:50 UTCGHSA enrichment
  30. 2026-09-14 14:28 UTCGHSA enrichment
  31. 2026-09-14 10:34 UTCGHSA enrichment
  32. 2026-09-14 06:38 UTCGHSA enrichment
  33. 2026-09-14 02:45 UTCGHSA enrichment
  34. 2026-09-13 22:49 UTCGHSA enrichment
  35. 2026-09-13 18:56 UTCEG score recompute
  36. 2026-09-13 18:56 UTCGHSA enrichment
  37. 2026-09-13 14:56 UTCGHSA enrichment
  38. 2026-09-13 10:46 UTCGHSA enrichment
  39. 2026-09-13 06:52 UTCGHSA enrichment
  40. 2026-09-13 02:52 UTCGHSA enrichment
  41. 2026-09-12 22:58 UTCGHSA enrichment
  42. 2026-09-12 19:04 UTCGHSA enrichment
  43. 2026-09-12 15:10 UTCEG score recompute
  44. 2026-09-12 15:10 UTCGHSA enrichment
  45. 2026-09-12 11:16 UTCGHSA enrichment
  46. 2026-09-12 07:22 UTCGHSA enrichment
  47. 2026-09-12 03:28 UTCGHSA enrichment
  48. 2026-09-11 23:34 UTCGHSA enrichment
  49. 2026-09-11 19:40 UTCGHSA enrichment
  50. 2026-09-11 15:46 UTCEG score recompute
  51. 2026-09-11 15:46 UTCGHSA enrichment
  52. 2026-09-11 14:53 UTCEPSS rescore
  53. 2026-09-11 14:53 UTCEPSS rescore
  54. 2026-09-11 11:52 UTCEG score recompute
  55. 2026-09-11 11:52 UTCGHSA enrichment
  56. 2026-09-11 07:50 UTCGHSA enrichment
  57. 2026-09-11 03:56 UTCGHSA enrichment
  58. 2026-09-11 00:01 UTCGHSA enrichment
  59. 2026-09-10 19:44 UTCGHSA enrichment
  60. 2026-09-10 15:47 UTCGHSA enrichment
  61. 2026-09-10 11:53 UTCEG score recompute
  62. 2026-09-10 11:53 UTCGHSA enrichment
  63. 2026-09-10 09:35 UTCEPSS rescore
  64. 2026-09-10 07:49 UTCGHSA enrichment
  65. 2026-09-10 03:55 UTCGHSA enrichment
  66. 2026-09-10 00:01 UTCGHSA enrichment
  67. 2026-09-09 16:58 UTCGHSA enrichment
  68. 2026-09-09 12:33 UTCGHSA enrichment
  69. 2026-09-09 08:39 UTCGHSA enrichment
  70. 2026-09-09 04:44 UTCGHSA enrichment
  71. 2026-09-09 00:44 UTCEG score recompute
  72. 2026-09-09 00:44 UTCGHSA enrichment
  73. 2026-09-08 22:01 UTCEPSS rescore
  74. 2026-09-08 11:24 UTCGHSA enrichment
  75. 2026-09-08 06:44 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-77991?
CVE-2026-77991 is a critical vulnerability published on August 27, 2026. Joomla Extension - joomlaeventmanager.net - Privileged remote code execution in Joomla Event Manager < 5.0.1 - The administrator source model allows to write dangerous file type incl. PHP, leading to remote code execution.
When was CVE-2026-77991 disclosed?
CVE-2026-77991 was first published in the National Vulnerability Database on August 27, 2026, with the most recent update 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-2026-77991 actively exploited?
CVE-2026-77991 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 64.6% of all scored CVEs.
What is the CVSS score of CVE-2026-77991?
CVE-2026-77991 has a CVSS v3 base score of 9.4 (NVD).
How do I remediate CVE-2026-77991?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77991, 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

Explore the affected products and dependency analysis for CVE-2026-77991

Explore →

Is Your Infrastructure Affected by CVE-2026-77991?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs