CVE-2026-4696

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-03-24. 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.

Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

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
40%
KEV
Not listed

Published

March 24, 2026

Last Modified

July 15, 2026

Advisory Details (10)

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

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:6188
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:5932
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:5931
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:5930
generic

Security Vulnerabilities fixed in Thunderbird 140.9 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-24/
generic

Security Vulnerabilities fixed in Thunderbird 149 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-23/
generic

Security Vulnerabilities fixed in Firefox ESR 140.9 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-22/
generic

Security Vulnerabilities fixed in Firefox ESR 115.34 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-21/
generic

Security Vulnerabilities fixed in Firefox 149 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-20/
generic

2020190 - (CVE-2026-4696) Use-after-free in FontFace.loaded promise resolution via thenable check

https://bugzilla.mozilla.org/show_bug.cgi?id=2020190

Vendor Advisories for CVE-2026-4696(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-0:140.9.0-1.el8_42026-04-20redhat
redhatfirefox-0:140.9.0-1.el7_92026-04-16redhat
redhatthunderbird-0:140.9.0-1.el10_02026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_62026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_22026-04-15redhat
redhatthunderbird-0:140.9.0-1.el8_22026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_42026-04-15redhat
redhatthunderbird-0:140.9.0-1.el8_82026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_02026-04-15redhat
redhatthunderbird-0:140.9.0-1.el8_62026-04-15redhat
redhatfirefox-0:140.9.0-1.el9_42026-04-13redhat
redhatfirefox-0:140.9.0-1.el8_22026-04-13redhat
redhatfirefox-0:140.9.0-1.el8_62026-04-13redhat
redhatfirefox-0:140.9.0-1.el8_82026-04-13redhat
redhatfirefox-0:140.9.0-1.el9_22026-04-13redhat
redhatfirefox-0:140.9.0-1.el9_02026-04-13redhat
redhatfirefox-0:140.9.0-1.el9_62026-04-13redhat
redhatfirefox-0:140.9.0-1.el8_42026-04-13redhat
redhatfirefox-0:140.9.0-1.el10_02026-04-13redhat
redhatthunderbird-0:140.9.0-1.el8_102026-04-07redhat
redhatthunderbird-0:140.9.0-1.el10_12026-04-01redhat
redhatthunderbird-0:140.9.0-1.el9_72026-03-30redhat
redhatfirefox-0:140.9.0-1.el10_12026-03-26redhat
redhatfirefox-0:140.9.0-1.el9_72026-03-26redhat
redhatfirefox-0:140.9.0-1.el8_102026-03-26redhat

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 (255 versions)140.9.0esr-1~deb11u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (306 versions)1:140.9.0esr-1~deb11u1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 140.8.0esr-1~deb13u1 (161 versions)140.9.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:140.9.0esr-1~deb11u1 (191 versions)1:140.9.0esr-1~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.8.0esr-1~deb13u1 (36 versions)140.9.0esr-1~deb13u1—
thunderbird1:128.13.0esr-1 ... 1:140.9.0esr-1~deb11u1 (46 versions)1:140.9.0esr-1~deb13u1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.0esr-1~deb13u1 (39 versions)140.9.0esr-1—
thunderbird1:128.13.0esr-1 ... 1:140.9.0esr-1~deb13u1 (48 versions)1:140.9.0esr-1—

Weakness Classification(2)

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 6× in last 7d / 82× 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 231 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-4696?
CVE-2026-4696 is a critical vulnerability published on March 24, 2026. Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
When was CVE-2026-4696 disclosed?
CVE-2026-4696 was first published in the National Vulnerability Database on March 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-2026-4696 actively exploited?
CVE-2026-4696 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 60.1% of all scored CVEs.
What is the CVSS score of CVE-2026-4696?
CVE-2026-4696 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-4696?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4696, 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-2026-4696

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