CVE-2026-2784

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-02-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
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.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

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
36%
KEV
Not listed

Published

February 24, 2026

Last Modified

June 17, 2026

Advisory Details (5)

Auto-updated Aug 31, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Thunderbird 140.8 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-17/
generic

Security Vulnerabilities fixed in Thunderbird 148 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-16/
generic

Security Vulnerabilities fixed in Firefox ESR 140.8 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-15/
generic

Security Vulnerabilities fixed in Firefox 148 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-13/
generic

2012984 - (CVE-2026-2784) bypass CSP with fetch with keepalive: true

https://bugzilla.mozilla.org/show_bug.cgi?id=2012984

Vendor Advisories for CVE-2026-2784(20)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(25)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatthunderbird-0:140.8.0-1.el8_22026-03-12redhat
redhatthunderbird-0:140.8.0-2.el10_02026-03-11redhat
redhatfirefox-0:140.8.0-2.el9_22026-03-10redhat
redhatfirefox-0:140.8.0-2.el10_02026-03-09redhat
redhatthunderbird-0:140.8.0-1.el8_82026-03-09redhat
redhatthunderbird-0:140.8.0-2.el8_42026-03-09redhat
redhatthunderbird-0:140.8.0-1.el9_62026-03-09redhat
redhatthunderbird-0:140.8.0-1.el9_42026-03-09redhat
redhatthunderbird-0:140.8.0-1.el9_02026-03-09redhat
redhatfirefox-0:140.8.0-2.el7_92026-03-09redhat
redhatthunderbird-0:140.8.0-1.el9_22026-03-09redhat
redhatthunderbird-0:140.8.0-1.el8_62026-03-09redhat
redhatfirefox-0:140.8.0-2.el9_62026-03-02redhat
redhatfirefox-0:140.8.0-2.el8_22026-03-02redhat
redhatfirefox-0:140.8.0-2.el8_62026-03-02redhat
redhatfirefox-0:140.8.0-2.el9_02026-03-02redhat
redhatthunderbird-0:140.8.0-1.el9_72026-03-02redhat
redhatthunderbird-0:140.8.0-1.el8_102026-03-02redhat
redhatthunderbird-0:140.8.0-2.el10_12026-03-02redhat
redhatfirefox-0:140.8.0-2.el8_82026-03-02redhat
redhatfirefox-0:140.8.0-2.el9_42026-03-02redhat
redhatfirefox-0:140.8.0-2.el8_42026-03-02redhat
redhatfirefox-0:140.8.0-2.el9_72026-02-25redhat
redhatfirefox-0:140.8.0-2.el8_102026-02-25redhat
redhatfirefox-0:140.8.0-2.el10_12026-02-25redhat

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 (251 versions)140.8.0esr-1~deb11u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (302 versions)1:140.8.0esr-1~deb11u1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 140.8.0esr-1~deb11u1 (158 versions)140.8.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:140.8.0esr-1~deb11u1 (187 versions)1:140.8.0esr-1~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.8.0esr-1~deb12u1 (34 versions)140.8.0esr-1~deb13u1—
thunderbird1:128.13.0esr-1 ... 1:140.8.0esr-1~deb12u1 (43 versions)1:140.8.0esr-1~deb13u1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.8.0esr-1~deb13u1 (35 versions)140.8.0esr-1—
thunderbird1:128.13.0esr-1 ... 1:140.8.0esr-1~deb13u1 (44 versions)1:140.8.0esr-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(5)

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 8× in last 7d / 73× 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 237 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-2784?
CVE-2026-2784 is a critical vulnerability published on February 24, 2026. Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
When was CVE-2026-2784 disclosed?
CVE-2026-2784 was first published in the National Vulnerability Database on February 24, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-2784 actively exploited?
CVE-2026-2784 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 64.0% of all scored CVEs.
What is the CVSS score of CVE-2026-2784?
CVE-2026-2784 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-2784?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-2784, 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-2026-2784

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