CVE-2026-8401

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-05-12. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
59(Track)
EG Risk 59/100SSVC: 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
Severity98% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
24%
KEV
Not listed

Published

May 12, 2026

Last Modified

July 15, 2026

Advisory Details (10)

Auto-updated Jul 25, 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 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 150.0.3 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-45/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2038679
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:22325
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:21382
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:21381
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:21380
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:21378

Vendor Advisories for CVE-2026-8401(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.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_82026-06-17redhat
redhatthunderbird-0:140.11.0-1.el10_02026-06-17redhat
redhatfirefox-0:140.11.0-1.el7_92026-06-17redhat
redhatthunderbird-0:140.11.0-1.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_42026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_22026-06-17redhat
redhatthunderbird-0:140.11.0-1.el9_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_42026-06-17redhat
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_42026-06-16redhat
redhatthunderbird-0:140.11.0-1.el9_22026-06-16redhat
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 / 43× 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 279 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-8401?
CVE-2026-8401 is a critical vulnerability published on May 12, 2026. Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
When was CVE-2026-8401 disclosed?
CVE-2026-8401 was first published in the National Vulnerability Database on May 12, 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-2026-8401 actively exploited?
CVE-2026-8401 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 76.3% of all scored CVEs.
What is the CVSS score of CVE-2026-8401?
CVE-2026-8401 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-8401?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8401, 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

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