CVE-2026-12299

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

Score 5.4 from GitHub Security Advisory published 2026-06-16. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

CVSS v3
5.4
EG Score
5.4MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
EPSS PROB
0.3%
EPSS %ILE
21st
KEV
Not listed

Published

June 16, 2026

Last Modified

July 15, 2026

Advisory Details (4)

Auto-updated Jun 16, 2026
Patch available.
generic

Security Vulnerabilities fixed in Firefox ESR 115.37 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-59/
generic

Security Vulnerabilities fixed in Firefox ESR 140.12 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-58/
generic

Security Vulnerabilities fixed in Firefox 152 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-57/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2043139

Vendor Advisories for CVE-2026-12299(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 / EcosystemFix (by version range) / PatchReleasedSource
redhatthunderbird-0:140.12.0-1.el9_22026-07-15redhat
redhatthunderbird-0:140.12.0-1.el8_82026-07-14redhat
redhatthunderbird-0:140.12.0-1.el8_62026-07-14redhat
redhatthunderbird-0:140.12.0-1.el8_42026-07-14redhat
redhatfirefox-0:140.12.0-1.el7_92026-07-13redhat
redhatthunderbird-0:140.12.0-1.el10_02026-07-13redhat
redhatfirefox-0:140.12.0-1.el9_42026-07-13redhat
redhatthunderbird-0:140.12.0-1.el9_42026-07-13redhat
redhatthunderbird-0:140.12.0-1.el9_62026-07-13redhat
redhatfirefox-0:140.12.0-1.el9_62026-07-09redhat
redhatfirefox-0:140.12.0-1.el8_62026-07-09redhat
redhatfirefox-0:140.12.0-1.el8_42026-07-07redhat
redhatfirefox-0:140.12.0-1.el10_02026-07-07redhat
redhatfirefox-0:140.12.0-1.el8_82026-07-07redhat
redhatfirefox-0:140.12.0-1.el9_22026-07-07redhat
redhatthunderbird-0:140.12.0-1.el8_102026-06-30redhat
redhatthunderbird-0:140.12.0-1.el10_22026-06-29redhat
redhatthunderbird-0:140.12.0-1.el9_82026-06-25redhat
redhatfirefox-0:140.12.0-1.el10_22026-06-22redhat
redhatfirefox-0:140.12.0-1.el8_102026-06-22redhat
redhatfirefox-0:140.12.0-1.el9_82026-06-22redhat

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 rangeFix by version rangeDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (279 versions)
  • every version up to 140.12.0esr-1~deb11u1: fixed in 140.12.0esr-1~deb11u1
—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (330 versions)
  • every version up to 1:140.12.0esr-1~deb11u1: fixed in 1:140.12.0esr-1~deb11u1
—
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (186 versions)
  • every version up to 140.12.0esr-1~deb12u1: fixed in 140.12.0esr-1~deb12u1
—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (215 versions)
  • every version up to 1:140.12.0esr-1~deb12u1: fixed in 1:140.12.0esr-1~deb12u1
—
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (62 versions)
  • every version up to 140.12.0esr-1~deb13u1: fixed in 140.12.0esr-1~deb13u1
—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (71 versions)
  • every version up to 1:140.12.0esr-1~deb13u1: fixed in 1:140.12.0esr-1~deb13u1
—
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (63 versions)
  • every version up to 140.12.0esr-1: fixed in 140.12.0esr-1
—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (72 versions)
  • every version up to 1:140.12.0esr-1: fixed in 1:140.12.0esr-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 7× in last 7d / 24× 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 240 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-12299?
CVE-2026-12299 is a medium vulnerability published on June 16, 2026. JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
When was CVE-2026-12299 disclosed?
CVE-2026-12299 was first published on June 16, 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-2026-12299 actively exploited?
CVE-2026-12299 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (21st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-12299?
CVE-2026-12299 has a CVSS v3.1 base score of 5.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-12299?
A fix for CVE-2026-12299 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-12299 are linked in the Vendor Advisories panel on this page.

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