CVE-2026-16406

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-21. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 5 sources updated this week
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0

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

Mitigation bypass in the Networking component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVSS v3
9.1
EG Score
9.1(high)
EG Risk
56(Track)
EG Risk 56/100SSVC: 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
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
15.9%
KEV
Not listed

Published

July 21, 2026

Last Modified

July 22, 2026

Advisory Details (2)

Auto-updated Jul 21, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Firefox 153 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-68/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2040382

Vendor Advisories for CVE-2026-16406(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 152× in last 7d / 152× 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 152 total refreshes for this CVE.

  1. 2026-07-23 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:05 UTCEG score recompute
  4. 2026-07-22 23:11 UTCEG score recompute
  5. 2026-07-22 23:10 UTCGHSA enrichment
  6. 2026-07-22 14:08 UTCEPSS rescore
  7. 2026-07-21 19:45 UTCEG score recompute▲ 9.10
  8. 2026-07-21 19:45 UTCGHSA enrichment
  9. 2026-07-21 19:43 UTCMITRE cvelistV5CVSS v3 → 9.1 · severity → CRITICAL
  10. 2026-07-21 19:16 UTCGHSA enrichment
  11. 2026-07-21 19:12 UTCGHSA enrichment
  12. 2026-07-21 19:12 UTCGHSA enrichment
  13. 2026-07-21 19:10 UTCGHSA enrichment
  14. 2026-07-21 19:09 UTCGHSA enrichment
  15. 2026-07-21 19:07 UTCGHSA enrichment
  16. 2026-07-21 19:05 UTCGHSA enrichment
  17. 2026-07-21 19:05 UTCGHSA enrichment
  18. 2026-07-21 19:04 UTCGHSA enrichment
  19. 2026-07-21 18:58 UTCGHSA enrichment
  20. 2026-07-21 18:41 UTCGHSA enrichment
  21. 2026-07-21 18:40 UTCGHSA enrichment
  22. 2026-07-21 18:37 UTCGHSA enrichment
  23. 2026-07-21 18:35 UTCGHSA enrichment
  24. 2026-07-21 18:34 UTCGHSA enrichment
  25. 2026-07-21 18:33 UTCGHSA enrichment
Show 75 more
  1. 2026-07-21 18:31 UTCGHSA enrichment
  2. 2026-07-21 18:31 UTCGHSA enrichment
  3. 2026-07-21 18:28 UTCGHSA enrichment
  4. 2026-07-21 18:26 UTCGHSA enrichment
  5. 2026-07-21 18:24 UTCGHSA enrichment
  6. 2026-07-21 18:23 UTCGHSA enrichment
  7. 2026-07-21 18:20 UTCGHSA enrichment
  8. 2026-07-21 18:20 UTCGHSA enrichment
  9. 2026-07-21 18:18 UTCGHSA enrichment
  10. 2026-07-21 18:18 UTCGHSA enrichment
  11. 2026-07-21 18:15 UTCGHSA enrichment
  12. 2026-07-21 18:14 UTCGHSA enrichment
  13. 2026-07-21 18:12 UTCGHSA enrichment
  14. 2026-07-21 18:10 UTCGHSA enrichment
  15. 2026-07-21 18:08 UTCGHSA enrichment
  16. 2026-07-21 18:07 UTCGHSA enrichment
  17. 2026-07-21 18:06 UTCGHSA enrichment
  18. 2026-07-21 18:02 UTCGHSA enrichment
  19. 2026-07-21 18:01 UTCGHSA enrichment
  20. 2026-07-21 17:59 UTCGHSA enrichment
  21. 2026-07-21 17:58 UTCGHSA enrichment
  22. 2026-07-21 17:57 UTCGHSA enrichment
  23. 2026-07-21 17:55 UTCGHSA enrichment
  24. 2026-07-21 17:55 UTCGHSA enrichment
  25. 2026-07-21 17:52 UTCGHSA enrichment
  26. 2026-07-21 17:50 UTCGHSA enrichment
  27. 2026-07-21 17:49 UTCGHSA enrichment
  28. 2026-07-21 17:48 UTCGHSA enrichment
  29. 2026-07-21 17:47 UTCGHSA enrichment
  30. 2026-07-21 17:44 UTCGHSA enrichment
  31. 2026-07-21 17:43 UTCGHSA enrichment
  32. 2026-07-21 17:42 UTCGHSA enrichment
  33. 2026-07-21 17:42 UTCGHSA enrichment
  34. 2026-07-21 17:40 UTCGHSA enrichment
  35. 2026-07-21 17:37 UTCGHSA enrichment
  36. 2026-07-21 17:34 UTCGHSA enrichment
  37. 2026-07-21 17:32 UTCGHSA enrichment
  38. 2026-07-21 17:32 UTCGHSA enrichment
  39. 2026-07-21 17:30 UTCGHSA enrichment
  40. 2026-07-21 17:29 UTCGHSA enrichment
  41. 2026-07-21 17:27 UTCGHSA enrichment
  42. 2026-07-21 17:25 UTCGHSA enrichment
  43. 2026-07-21 17:25 UTCGHSA enrichment
  44. 2026-07-21 17:18 UTCGHSA enrichment
  45. 2026-07-21 17:16 UTCGHSA enrichment
  46. 2026-07-21 17:14 UTCGHSA enrichment
  47. 2026-07-21 17:13 UTCGHSA enrichment
  48. 2026-07-21 17:12 UTCGHSA enrichment
  49. 2026-07-21 17:09 UTCGHSA enrichment
  50. 2026-07-21 17:08 UTCGHSA enrichment
  51. 2026-07-21 17:08 UTCGHSA enrichment
  52. 2026-07-21 17:05 UTCGHSA enrichment
  53. 2026-07-21 17:03 UTCGHSA enrichment
  54. 2026-07-21 17:02 UTCGHSA enrichment
  55. 2026-07-21 17:02 UTCGHSA enrichment
  56. 2026-07-21 17:00 UTCGHSA enrichment
  57. 2026-07-21 16:59 UTCGHSA enrichment
  58. 2026-07-21 16:58 UTCGHSA enrichment
  59. 2026-07-21 16:57 UTCGHSA enrichment
  60. 2026-07-21 16:55 UTCGHSA enrichment
  61. 2026-07-21 16:54 UTCGHSA enrichment
  62. 2026-07-21 16:53 UTCGHSA enrichment
  63. 2026-07-21 16:52 UTCGHSA enrichment
  64. 2026-07-21 16:51 UTCGHSA enrichment
  65. 2026-07-21 16:50 UTCGHSA enrichment
  66. 2026-07-21 16:48 UTCGHSA enrichment
  67. 2026-07-21 16:47 UTCGHSA enrichment
  68. 2026-07-21 16:47 UTCGHSA enrichment
  69. 2026-07-21 16:46 UTCGHSA enrichment
  70. 2026-07-21 16:45 UTCGHSA enrichment
  71. 2026-07-21 16:43 UTCGHSA enrichment
  72. 2026-07-21 16:42 UTCGHSA enrichment
  73. 2026-07-21 16:41 UTCGHSA enrichment
  74. 2026-07-21 16:40 UTCGHSA enrichment
  75. 2026-07-21 16:40 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-16406?
CVE-2026-16406 is a critical vulnerability published on July 21, 2026. Mitigation bypass in the Networking component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.
When was CVE-2026-16406 disclosed?
CVE-2026-16406 was first published in the National Vulnerability Database on July 21, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16406 actively exploited?
CVE-2026-16406 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 15.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-16406?
CVE-2026-16406 has a CVSS v3.1 base score of 9.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-16406?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16406, 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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