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
Trending — 4 sources updated this week
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 Aug 22, 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.

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 9× in last 7d / 169× 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 448 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 18:25 UTCEG score recompute
  4. 2026-08-23 18:25 UTCVendor advisory
  5. 2026-08-23 18:25 UTCGHSA enrichment
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-20 22:56 UTCEPSS rescore
  9. 2026-08-19 17:04 UTCEPSS rescore
  10. 2026-08-18 13:49 UTCEPSS rescore
  11. 2026-08-18 13:49 UTCEPSS rescore
  12. 2026-08-17 14:42 UTCEG score recompute
  13. 2026-08-17 14:42 UTCVendor advisory
  14. 2026-08-17 14:42 UTCGHSA enrichment
  15. 2026-08-17 13:47 UTCEPSS rescore
  16. 2026-08-17 10:55 UTCEG score recompute
  17. 2026-08-17 10:55 UTCVendor advisory
  18. 2026-08-17 10:55 UTCGHSA enrichment
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 14:56 UTCEPSS rescore
  21. 2026-08-16 11:43 UTCVendor advisory
  22. 2026-08-16 11:43 UTCGHSA enrichment
  23. 2026-08-16 08:00 UTCVendor advisory
  24. 2026-08-16 08:00 UTCGHSA enrichment
  25. 2026-08-16 04:17 UTCEG score recompute
Show 75 more
  1. 2026-08-16 04:17 UTCVendor advisory
  2. 2026-08-16 04:17 UTCGHSA enrichment
  3. 2026-08-16 02:15 UTCEPSS rescore
  4. 2026-08-15 01:31 UTCEPSS rescore
  5. 2026-08-15 01:28 UTCVendor advisory
  6. 2026-08-15 01:28 UTCGHSA enrichment
  7. 2026-08-14 21:45 UTCVendor advisory
  8. 2026-08-14 21:45 UTCGHSA enrichment
  9. 2026-08-14 18:01 UTCVendor advisory
  10. 2026-08-14 18:01 UTCGHSA enrichment
  11. 2026-08-14 13:59 UTCVendor advisory
  12. 2026-08-14 13:59 UTCGHSA enrichment
  13. 2026-08-14 10:15 UTCVendor advisory
  14. 2026-08-14 10:15 UTCGHSA enrichment
  15. 2026-08-14 06:32 UTCVendor advisory
  16. 2026-08-14 06:32 UTCGHSA enrichment
  17. 2026-08-14 02:48 UTCEG score recompute
  18. 2026-08-14 02:48 UTCVendor advisory
  19. 2026-08-14 02:48 UTCGHSA enrichment
  20. 2026-08-13 22:00 UTCEPSS rescore
  21. 2026-08-13 08:16 UTCVendor advisory
  22. 2026-08-13 08:16 UTCGHSA enrichment
  23. 2026-08-13 03:29 UTCVendor advisory
  24. 2026-08-13 03:29 UTCGHSA enrichment
  25. 2026-08-12 23:45 UTCVendor advisory
  26. 2026-08-12 23:45 UTCGHSA enrichment
  27. 2026-08-12 20:02 UTCVendor advisory
  28. 2026-08-12 20:02 UTCGHSA enrichment
  29. 2026-08-12 16:19 UTCEG score recompute
  30. 2026-08-12 16:19 UTCVendor advisory
  31. 2026-08-12 16:18 UTCGHSA enrichment
  32. 2026-08-12 13:51 UTCEPSS rescore
  33. 2026-08-11 23:09 UTCVendor advisory
  34. 2026-08-11 23:09 UTCGHSA enrichment
  35. 2026-08-11 19:26 UTCVendor advisory
  36. 2026-08-11 19:26 UTCGHSA enrichment
  37. 2026-08-11 15:43 UTCEG score recompute
  38. 2026-08-11 15:43 UTCVendor advisory
  39. 2026-08-11 15:43 UTCGHSA enrichment
  40. 2026-08-11 13:43 UTCEPSS rescore
  41. 2026-08-11 08:32 UTCVendor advisory
  42. 2026-08-11 08:32 UTCGHSA enrichment
  43. 2026-08-11 04:48 UTCVendor advisory
  44. 2026-08-11 04:48 UTCGHSA enrichment
  45. 2026-08-11 01:05 UTCEG score recompute
  46. 2026-08-11 01:05 UTCVendor advisory
  47. 2026-08-11 01:05 UTCGHSA enrichment
  48. 2026-08-11 00:00 UTCEPSS rescore
  49. 2026-08-10 12:41 UTCVendor advisory
  50. 2026-08-10 12:41 UTCGHSA enrichment
  51. 2026-08-10 08:47 UTCVendor advisory
  52. 2026-08-10 08:47 UTCGHSA enrichment
  53. 2026-08-10 05:04 UTCVendor advisory
  54. 2026-08-10 05:04 UTCGHSA enrichment
  55. 2026-08-10 01:21 UTCVendor advisory
  56. 2026-08-10 01:21 UTCGHSA enrichment
  57. 2026-08-09 21:38 UTCVendor advisory
  58. 2026-08-09 21:38 UTCGHSA enrichment
  59. 2026-08-09 17:55 UTCVendor advisory
  60. 2026-08-09 17:55 UTCGHSA enrichment
  61. 2026-08-09 14:12 UTCEG score recompute
  62. 2026-08-09 14:12 UTCVendor advisory
  63. 2026-08-09 14:12 UTCGHSA enrichment
  64. 2026-08-09 13:47 UTCEPSS rescore
  65. 2026-08-09 10:28 UTCVendor advisory
  66. 2026-08-09 10:28 UTCGHSA enrichment
  67. 2026-08-09 05:51 UTCVendor advisory
  68. 2026-08-09 05:51 UTCGHSA enrichment
  69. 2026-08-09 02:08 UTCEG score recompute
  70. 2026-08-09 02:08 UTCVendor advisory
  71. 2026-08-09 02:08 UTCGHSA enrichment
  72. 2026-08-08 16:37 UTCEPSS rescore
  73. 2026-08-08 10:51 UTCVendor advisory
  74. 2026-08-08 10:51 UTCGHSA enrichment
  75. 2026-08-08 06:49 UTCVendor advisory

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 76.5% 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-8401

Explore →

Is Your Infrastructure Affected by CVE-2026-8401?

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

Start Free Scan →Browse All CVEs