CVE-2026-66490

MEDIUMPre-NVD 6.16.1
EchelonGraph scoreMEDIUM confidence

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

Score 6.1 from GitHub Security Advisory published 2026-07-29. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory

Also known asEUVD-2026-50333 (ENISA EUVD) · GHSA-6432-frr4-pgf6 (GitHub Security Advisories)Source: ENISA EUVD

6.1EG
EchelonGraph verdictMonitorNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.1Exploit: None knownExposed services: Not assessed

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

The CVE record's description, written by its CNA (Joomla! Project), states the affected versions: "Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2". No release containing a fix is confirmed on record.

Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2

CVSS v3
6.1
EG Score
6.1MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity61% × 45%
Impact severity (EG Severity): CVSS 6.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 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 every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
0.3%
EPSS %ILE
18th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.1): severity, escalated by confirmed exploitation. This CVE's 6.1 is its impact severity (EG Severity), not escalated.

EG Severity
6.1 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (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

July 29, 2026

Last Modified

October 23, 2026

Advisory Details (2)

Auto-updated Jul 29, 2026
No fix on record yet.
Web page

Build a Joomla Site — Joomla Website Builder Gridbox

https://www.balbooa.com/gridbox
Web page

Gridbox: 23 More Critical Vulnerabilities | mySites.guru

https://mysites.guru/blog/gridbox-23-critical-vulnerabilities/

Vendor Advisories for CVE-2026-66490(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 7× in last 7d / 45× 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.

Showing the most recent 100 of 203 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 103 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  4. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  5. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  6. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  7. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  8. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  9. 2026-10-25 14:11 UTCEG score recompute
  10. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  11. 2026-10-23 23:31 UTCEG score recompute
  12. 2026-10-23 23:31 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  13. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  14. 2026-10-22 19:36 UTCEG score recompute
  15. 2026-10-22 19:36 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  16. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  17. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  18. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  19. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  20. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  21. 2026-10-18 03:20 UTCEG score recompute
  22. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  23. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  24. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  25. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
Show 75 more
  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  3. 2026-10-12 15:46 UTCEG score recompute
  4. 2026-10-11 19:31 UTCEG score recompute
  5. 2026-10-11 16:46 UTCEG score recompute
  6. 2026-10-11 14:07 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  10. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  12. 2026-10-07 00:01 UTCEG score recompute
  13. 2026-10-07 00:01 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  15. 2026-10-05 20:53 UTCEG score recompute
  16. 2026-10-05 20:53 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  17. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  18. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  19. 2026-10-04 07:02 UTCEG score recompute
  20. 2026-10-04 07:02 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  21. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  22. 2026-10-02 17:58 UTCEG score recompute
  23. 2026-10-02 17:58 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  24. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  25. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  26. 2026-10-01 03:36 UTCEG score recompute
  27. 2026-10-01 03:36 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  28. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  29. 2026-09-29 07:36 UTCEG score recompute
  30. 2026-09-29 07:36 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  31. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  32. 2026-09-28 03:17 UTCEG score recompute
  33. 2026-09-28 03:17 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  34. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  35. 2026-09-25 05:41 UTCEG score recompute
  36. 2026-09-25 05:41 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  37. 2026-09-23 21:50 UTCEG score recompute
  38. 2026-09-23 21:50 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  39. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  40. 2026-09-22 15:49 UTCEG score recompute
  41. 2026-09-22 15:49 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  42. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  43. 2026-09-20 04:32 UTCEG score recompute
  44. 2026-09-20 04:32 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  45. 2026-09-19 04:55 UTCEG score recompute
  46. 2026-09-19 04:54 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  47. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  48. 2026-09-18 01:42 UTCEG score recompute
  49. 2026-09-18 01:42 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  50. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  51. 2026-09-16 11:49 UTCEG score recompute
  52. 2026-09-16 11:49 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  53. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  54. 2026-09-15 08:07 UTCEG score recompute
  55. 2026-09-15 08:07 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  56. 2026-09-14 05:23 UTCEG score recompute
  57. 2026-09-14 05:23 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  58. 2026-09-13 05:55 UTCEG score recompute
  59. 2026-09-13 05:55 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  60. 2026-09-12 06:27 UTCEG score recompute
  61. 2026-09-12 06:27 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  62. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  63. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  64. 2026-09-11 06:47 UTCEG score recompute
  65. 2026-09-11 06:47 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  66. 2026-09-10 07:18 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  67. 2026-09-09 07:49 UTCEG score recompute
  68. 2026-09-09 07:49 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  69. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  70. 2026-09-07 20:50 UTCEG score recompute
  71. 2026-09-07 20:50 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1
  72. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  73. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  74. 2026-09-06 10:59 UTCEG score recompute
  75. 2026-09-06 10:59 UTCGHSA enrichmentGHSA-6432-frr4-pgf6 · GitHub CVSS 6.1

Frequently asked(5)

What is CVE-2026-66490?
CVE-2026-66490 is a medium-severity vulnerability; its CVE record was published on July 29, 2026. Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2
When was the CVE record for CVE-2026-66490 published?
The CVE record for CVE-2026-66490 was published on July 29, 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 October 23, 2026; the record at its source may have been updated since.
Is CVE-2026-66490 actively exploited?
CVE-2026-66490 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (18th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66490?
CVE-2026-66490 has a CVSS v3.1 base score of 6.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-66490?
No fix for CVE-2026-66490 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's description, written by its CNA (Joomla! Project), states the affected versions: "Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2". No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-66490 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66490

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