CVE-2026-8962

HIGHNVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2026-05-19. NVD baseline CVSS 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS v3
8.1
EG Score
8.1HIGHmedium confidence
EG Risk
37
EG Risk 37/100

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
Severity81% × 45%
Exploitation0% × 40%
Automatability0% × 15%
EPSS PROB
0.4%
EPSS %ILE
32nd
KEV
Not listed

Published

May 19, 2026

Last Modified

July 23, 2026

Advisory Details (5)

Auto-updated Jun 3, 2026
Patch available.
generic

Security Vulnerabilities fixed in Thunderbird 140.11 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-51/
generic

Security Vulnerabilities fixed in Thunderbird 151 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-50/
generic

Security Vulnerabilities fixed in Firefox ESR 140.11 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-48/
generic

Security Vulnerabilities fixed in Firefox 151 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-46/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2004804

Vendor Advisories for CVE-2026-8962(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 / EcosystemFix (by version range) / PatchReleasedSource
redhatfirefox-0:140.11.0-1.el10_02026-06-22redhat
redhatfirefox-0:140.11.0-1.el8_82026-06-17redhat
redhatthunderbird-0:140.11.0-1.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el7_92026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_42026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_22026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_62026-06-17redhat
redhatthunderbird-0:140.11.0-1.el10_02026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_42026-06-17redhat
redhatthunderbird-0:140.11.0-1.el9_62026-06-17redhat
redhatthunderbird-0:140.11.0-1.el8_82026-06-16redhat
redhatthunderbird-0:140.11.0-1.el8_42026-06-16redhat
redhatthunderbird-0:140.11.0-1.el9_22026-06-16redhat
redhatthunderbird-0:140.11.0-1.el9_42026-06-16redhat
redhatthunderbird-0:140.11.0-1.el8_102026-06-03redhat
redhatthunderbird-0:140.11.0-1.el10_22026-06-01redhat
redhatfirefox-0:140.11.0-1.el9_82026-05-27redhat
redhatfirefox-0:140.11.0-1.el10_22026-05-27redhat
redhatfirefox-0:140.11.0-1.el8_102026-05-27redhat
redhatthunderbird-0:140.11.0-1.el9_82026-05-27redhat

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 rangeFix by version rangeDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (275 versions)
  • every version up to 140.11.0esr-1~deb11u1: fixed in 140.11.0esr-1~deb11u1
—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (326 versions)
  • every version up to 1:140.11.0esr-1~deb11u1: fixed in 1:140.11.0esr-1~deb11u1
—
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (182 versions)
  • every version up to 140.11.0esr-1~deb12u1: fixed in 140.11.0esr-1~deb12u1
—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (211 versions)
  • every version up to 1:140.11.0esr-1~deb12u1: fixed in 1:140.11.0esr-1~deb12u1
—
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (58 versions)
  • every version up to 140.11.0esr-1~deb13u1: fixed in 140.11.0esr-1~deb13u1
—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (67 versions)
  • every version up to 1:140.11.0esr-1~deb13u1: fixed in 1:140.11.0esr-1~deb13u1
—
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (59 versions)
  • every version up to 140.11.0esr-1: fixed in 140.11.0esr-1
—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (68 versions)
  • every version up to 1:140.11.0esr-1: fixed in 1:140.11.0esr-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 6× in last 7d / 25× 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 303 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-8962?
CVE-2026-8962 is a high vulnerability published on May 19, 2026. Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
When was CVE-2026-8962 disclosed?
CVE-2026-8962 was first published on May 19, 2026, with the most recent update on July 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8962 actively exploited?
CVE-2026-8962 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (32nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-8962?
CVE-2026-8962 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-8962?
A fix for CVE-2026-8962 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-8962 are linked in the Vendor Advisories panel on this page.

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