CVE-2026-2799

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

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: 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%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
25%
KEV
Not listed

Published

February 24, 2026

Last Modified

July 15, 2026

Advisory Details (6)

Auto-updated Aug 29, 2026
Patch available. Sources: redhat.
redhat

Affected: Red Hat Enterprise Linux 10",

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2799.json
redhat

2442303 – (CVE-2026-2799) CVE-2026-2799 firefox: thunderbird: Use-after-free in the DOM: Core & HTML component

https://bugzilla.redhat.com/show_bug.cgi?id=2442303
redhat Patch Available

CVE-2026-2799 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-2799
generic

Security Vulnerabilities fixed in Thunderbird 148 — Mozilla

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

Security Vulnerabilities fixed in Firefox 148 — Mozilla

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

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2014551

Vendor Advisories for CVE-2026-2799(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 53× 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 196 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. 2026-08-30 19:17 UTCEPSS rescore
  5. 2026-08-30 01:22 UTCEPSS rescore
  6. 2026-08-28 21:41 UTCEPSS rescore
  7. 2026-08-27 14:25 UTCEPSS rescore
  8. 2026-08-26 14:46 UTCEPSS rescore
  9. 2026-08-25 13:49 UTCEPSS rescore
  10. 2026-08-24 14:17 UTCEPSS rescore
  11. 2026-08-23 00:19 UTCEPSS rescore
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-20 22:55 UTCEPSS rescore
  14. 2026-08-20 22:55 UTCEPSS rescore
  15. 2026-08-19 17:03 UTCEPSS rescore
  16. 2026-08-18 13:48 UTCEPSS rescore
  17. 2026-08-17 13:47 UTCEPSS rescore
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 02:14 UTCEPSS rescore
  20. 2026-08-15 01:31 UTCEG score recompute
  21. 2026-08-15 01:31 UTCGHSA enrichment
  22. 2026-08-15 01:30 UTCEPSS rescore
  23. 2026-08-14 21:28 UTCGHSA enrichment
  24. 2026-08-14 13:09 UTCGHSA enrichment
  25. 2026-08-14 09:06 UTCEG score recompute
Show 75 more
  1. 2026-08-14 09:06 UTCGHSA enrichment
  2. 2026-08-13 22:00 UTCEPSS rescore
  3. 2026-08-13 01:06 UTCEG score recompute
  4. 2026-08-13 01:06 UTCGHSA enrichment
  5. 2026-08-12 13:50 UTCEPSS rescore
  6. 2026-08-12 00:53 UTCEG score recompute
  7. 2026-08-12 00:53 UTCGHSA enrichment
  8. 2026-08-11 06:37 UTCEG score recompute
  9. 2026-08-11 06:37 UTCGHSA enrichment
  10. 2026-08-11 00:00 UTCEPSS rescore
  11. 2026-08-10 13:17 UTCGHSA enrichment
  12. 2026-08-10 08:53 UTCGHSA enrichment
  13. 2026-08-10 02:13 UTCGHSA enrichment
  14. 2026-08-09 21:58 UTCGHSA enrichment
  15. 2026-08-09 17:54 UTCGHSA enrichment
  16. 2026-08-09 13:51 UTCEG score recompute
  17. 2026-08-09 13:51 UTCGHSA enrichment
  18. 2026-08-09 13:46 UTCEPSS rescore
  19. 2026-08-09 08:44 UTCEG score recompute
  20. 2026-08-09 08:44 UTCGHSA enrichment
  21. 2026-08-08 16:37 UTCEPSS rescore
  22. 2026-08-08 09:00 UTCGHSA enrichment
  23. 2026-08-08 04:57 UTCGHSA enrichment
  24. 2026-08-08 00:54 UTCGHSA enrichment
  25. 2026-08-07 20:51 UTCEG score recompute
  26. 2026-08-07 20:51 UTCGHSA enrichment
  27. 2026-08-06 13:46 UTCEPSS rescore
  28. 2026-08-06 07:08 UTCGHSA enrichment
  29. 2026-08-06 03:05 UTCEG score recompute
  30. 2026-08-06 03:05 UTCGHSA enrichment
  31. 2026-08-05 19:17 UTCEPSS rescore
  32. 2026-08-04 15:10 UTCEPSS rescore
  33. 2026-08-04 05:58 UTCGHSA enrichment
  34. 2026-08-02 23:46 UTCGHSA enrichment
  35. 2026-08-02 19:41 UTCEG score recompute
  36. 2026-08-02 19:41 UTCGHSA enrichment
  37. 2026-08-02 02:26 UTCEPSS rescore
  38. 2026-08-01 04:16 UTCEPSS rescore
  39. 2026-07-30 16:27 UTCEPSS rescore
  40. 2026-07-30 01:30 UTCEPSS rescore
  41. 2026-07-28 15:36 UTCEPSS rescore
  42. 2026-07-26 14:54 UTCEPSS rescore
  43. 2026-07-26 14:54 UTCEPSS rescore
  44. 2026-07-25 14:18 UTCEPSS rescore
  45. 2026-07-25 14:17 UTCEPSS rescore
  46. 2026-07-24 14:17 UTCEPSS rescore
  47. 2026-07-23 14:18 UTCEPSS rescore
  48. 2026-07-23 14:18 UTCEPSS rescore
  49. 2026-07-23 03:08 UTCEG score recompute
  50. 2026-07-22 14:08 UTCEPSS rescore
  51. 2026-07-22 14:08 UTCEPSS rescore
  52. 2026-07-20 17:08 UTCEPSS rescore
  53. 2026-07-20 17:08 UTCEPSS rescore
  54. 2026-07-19 14:31 UTCEPSS rescore
  55. 2026-07-19 14:31 UTCEPSS rescore
  56. 2026-07-19 02:29 UTCEPSS rescore
  57. 2026-07-18 10:04 UTCEPSS rescore
  58. 2026-07-18 10:04 UTCEPSS rescore
  59. 2026-07-16 17:03 UTCEPSS rescore
  60. 2026-07-16 17:03 UTCEPSS rescore
  61. 2026-07-15 16:57 UTCEPSS rescore
  62. 2026-07-15 16:57 UTCEPSS rescore
  63. 2026-07-15 02:22 UTCNVD updateCVSS v3 → 9.8 · severity → CRITICAL
  64. 2026-07-15 02:00 UTCEPSS rescore
  65. 2026-07-15 02:00 UTCEPSS rescore
  66. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
  67. 2026-07-13 22:30 UTCEPSS rescore
  68. 2026-07-13 06:13 UTCEPSS rescore
  69. 2026-07-13 06:13 UTCEPSS rescore
  70. 2026-07-12 05:46 UTCEPSS rescore
  71. 2026-07-11 08:27 UTCEPSS rescore
  72. 2026-07-09 19:10 UTCEPSS rescore
  73. 2026-07-08 15:15 UTCEPSS rescore
  74. 2026-07-07 13:46 UTCEPSS rescore
  75. 2026-07-06 16:27 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-2799?
CVE-2026-2799 is a critical vulnerability published on February 24, 2026. Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.
When was CVE-2026-2799 disclosed?
CVE-2026-2799 was first published in the National Vulnerability Database on February 24, 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-2026-2799 actively exploited?
CVE-2026-2799 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 75.3% of all scored CVEs.
What is the CVSS score of CVE-2026-2799?
CVE-2026-2799 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-2799?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-2799, 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.

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