CVE-2026-8946

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-19. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
42.5%
KEV
Not listed

Published

May 19, 2026

Last Modified

June 30, 2026

Advisory Details (6)

Auto-updated May 19, 2026
No patch confirmed yet.
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 ESR 115.36 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-47/
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=2029070

Vendor Advisories for CVE-2026-8946(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-0:140.11.0-1.el10_02026-06-22redhat
redhatfirefox-0:140.11.0-1.el9_22026-06-17redhat
redhatthunderbird-0:140.11.0-1.el10_02026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_42026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_82026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_62026-06-17redhat
redhatthunderbird-0:140.11.0-1.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_42026-06-17redhat
redhatfirefox-0:140.11.0-1.el7_92026-06-17redhat
redhatthunderbird-0:140.11.0-1.el9_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_62026-06-17redhat
redhatthunderbird-0:140.11.0-1.el8_42026-06-16redhat
redhatthunderbird-0:140.11.0-1.el8_82026-06-16redhat
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
redhatthunderbird-0:140.11.0-1.el9_82026-05-27redhat
redhatfirefox-0:140.11.0-1.el9_82026-05-27redhat
redhatfirefox-0:140.11.0-1.el8_102026-05-27redhat
redhatfirefox-0:140.11.0-1.el10_22026-05-27redhat

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.

Weakness Classification(2)

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 9× in last 7d / 109× 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 162 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-8946?
CVE-2026-8946 is a high vulnerability published on May 19, 2026. Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
When was CVE-2026-8946 disclosed?
CVE-2026-8946 was first published in the National Vulnerability Database on May 19, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8946 actively exploited?
CVE-2026-8946 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 42.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8946?
CVE-2026-8946 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-8946?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8946, 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-2026-8946

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