CVE-2026-8388

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-05-12. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

A fix is available — apply it.

Incorrect boundary conditions in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.

CVSS v3
6.5
EG Score
6.5(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
Severity65% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
15%
KEV
Not listed

Published

May 12, 2026

Last Modified

July 15, 2026

Advisory Details (5)

Auto-updated Jun 13, 2026
No patch confirmed yet.
generic

Security Vulnerabilities fixed in Thunderbird 140.11 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-51/
generic

Security Vulnerabilities fixed in Firefox ESR 140.11 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-48/
generic

Security Vulnerabilities fixed in Firefox ESR 115.36 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-47/
generic

Security Vulnerabilities fixed in Firefox 150.0.3 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-45/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2036978

Vendor Advisories for CVE-2026-8388(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 / EcosystemFixed in / PatchReleasedSource
redhatfirefox-0:140.11.0-1.el10_02026-06-22redhat
redhatfirefox-0:140.11.0-1.el9_42026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_42026-06-17redhat
redhatthunderbird-0:140.11.0-1.el10_02026-06-17redhat
redhatthunderbird-0:140.11.0-1.el8_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el9_22026-06-17redhat
redhatfirefox-0:140.11.0-1.el7_92026-06-17redhat
redhatthunderbird-0:140.11.0-1.el9_62026-06-17redhat
redhatfirefox-0:140.11.0-1.el8_82026-06-17redhat
redhatthunderbird-0:140.11.0-1.el8_42026-06-16redhat
redhatthunderbird-0:140.11.0-1.el9_42026-06-16redhat
redhatthunderbird-0:140.11.0-1.el8_82026-06-16redhat
redhatthunderbird-0:140.11.0-1.el9_22026-06-16redhat
redhatthunderbird-0:140.11.0-1.el8_102026-06-03redhat
redhatthunderbird-0:140.11.0-1.el10_22026-06-01redhat
redhatfirefox-0:140.11.0-1.el9_82026-05-27redhat
redhatthunderbird-0:140.11.0-1.el9_82026-05-27redhat
redhatfirefox-0:140.11.0-1.el8_102026-05-27redhat
redhatfirefox-0:140.11.0-1.el10_22026-05-27redhat

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 (275 versions)140.11.0esr-1~deb11u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (326 versions)1:140.11.0esr-1~deb11u1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (182 versions)140.11.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (211 versions)1:140.11.0esr-1~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (58 versions)140.11.0esr-1~deb13u1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (67 versions)1:140.11.0esr-1~deb13u1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (59 versions)140.11.0esr-1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (68 versions)1:140.11.0esr-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 9× in last 7d / 71× 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 184 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-8388?
CVE-2026-8388 is a medium vulnerability published on May 12, 2026. Incorrect boundary conditions in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
When was CVE-2026-8388 disclosed?
CVE-2026-8388 was first published in the National Vulnerability Database on May 12, 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-2026-8388 actively exploited?
CVE-2026-8388 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 84.7% of all scored CVEs.
What is the CVSS score of CVE-2026-8388?
CVE-2026-8388 has a CVSS v3.1 base score of 6.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-8388?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8388, 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-2026-8388

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