CVE-2026-16405

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-21. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

A fix is available — apply it.

Information disclosure in the Networking: WebSockets component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
17%
KEV
Not listed

Published

July 21, 2026

Last Modified

July 22, 2026

Advisory Details (3)

Auto-updated Jul 21, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

Security Vulnerabilities fixed in Firefox ESR 140.13 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-70/
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=2036591

Vendor Advisories for CVE-2026-16405(20)

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

Patch Availability(21)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatfirefox-0:140.13.0-1.el10_02026-08-12redhat
redhatfirefox-0:140.13.0-1.el8_82026-08-12redhat
redhatfirefox-0:140.13.0-1.el9_42026-08-12redhat
redhatfirefox-0:140.13.0-1.el9_62026-08-12redhat
redhatfirefox-0:140.13.0-1.el8_42026-08-12redhat
redhatfirefox-0:140.13.0-1.el8_62026-08-12redhat
redhatfirefox-0:140.13.0-1.el9_22026-08-12redhat
redhatfirefox-0:140.13.0-1.el7_92026-08-12redhat
redhatthunderbird-0:140.13.0-1.el8_82026-08-11redhat
redhatthunderbird-0:140.13.0-1.el8_62026-08-11redhat
redhatthunderbird-0:140.13.0-1.el10_02026-08-11redhat
redhatthunderbird-0:140.13.0-1.el8_42026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_22026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_42026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_62026-08-11redhat
redhatthunderbird-0:140.13.0-1.el8_102026-08-04redhat
redhatthunderbird-0:140.13.0-1.el9_82026-08-04redhat
redhatfirefox-0:140.13.0-1.el9_82026-08-03redhat
redhatthunderbird-0:140.13.0-1.el10_22026-08-03redhat
redhatfirefox-0:140.13.0-1.el8_102026-07-28redhat
redhatfirefox-0:140.13.0-1.el10_22026-07-28redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(8 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (283 versions)140.13.0esr-1~deb11u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (334 versions)1:140.13.0esr-1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (190 versions)140.13.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (220 versions)1:140.13.0esr-2~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (66 versions)140.13.0esr-1~deb13u1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (76 versions)1:140.13.0esr-2~deb13u1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (67 versions)140.13.0esr-1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (73 versions)1:140.13.0esr-1—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 26× in last 7d / 126× 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 394 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-16405?
CVE-2026-16405 is a high vulnerability published on July 21, 2026. Information disclosure in the Networking: WebSockets component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
When was CVE-2026-16405 disclosed?
CVE-2026-16405 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-2026-16405 actively exploited?
CVE-2026-16405 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 82.7% of all scored CVEs.
What is the CVSS score of CVE-2026-16405?
CVE-2026-16405 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-16405?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16405, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-16405

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