CVE-2026-8946

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-19. 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: 1%CVSS: 7.5Exploit: None knownExposed: 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)
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%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
44%
KEV
Not listed

Published

May 19, 2026

Last Modified

July 15, 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
redhatthunderbird-0:140.11.0-1.el8_62026-06-17redhat
redhatthunderbird-0:140.11.0-1.el9_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_42026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_42026-06-17redhat
redhatthunderbird-0:140.11.0-1.el10_02026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_22026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_82026-06-17redhat
redhatfirefox-0:140.11.0-1.el7_92026-06-17redhat
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_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.

Affected Packages

(8 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (275 versions)140.11.0esr-1~deb11u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (326 versions)1:140.11.0esr-1~deb11u1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (182 versions)140.11.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (211 versions)1:140.11.0esr-1~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (58 versions)140.11.0esr-1~deb13u1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (67 versions)1:140.11.0esr-1~deb13u1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (59 versions)140.11.0esr-1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (68 versions)1:140.11.0esr-1—

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 15× in last 7d / 97× 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 244 total refreshes for this CVE.

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

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 July 15, 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 1% probability of exploitation in the next 30 days, which ranks it in the top 55.9% of all scored CVEs.
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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-8946

Explore →

Is Your Infrastructure Affected by CVE-2026-8946?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs