CVE-2026-12321

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
Trending — 3 sources updated this week
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

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

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.

CVSS v3
5.4
EG Score
5.4(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

June 16, 2026

Last Modified

June 16, 2026

Advisory Details (3)

Auto-updated Jun 16, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Thunderbird 152 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-60/
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=2032943

Vendor Advisories for CVE-2026-12321(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 15× 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 152 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-12321?
CVE-2026-12321 is a medium vulnerability published on June 16, 2026. JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.
When was CVE-2026-12321 disclosed?
CVE-2026-12321 was first published in the National Vulnerability Database on June 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-12321 actively exploited?
CVE-2026-12321 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 94.7% of all scored CVEs.
What is the CVSS score of CVE-2026-12321?
CVE-2026-12321 has a CVSS v3.1 base score of 5.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-12321?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-12321, 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

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