CVE-2026-3889

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-03-24. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
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.

Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

CVSS v3
6.5
EG Score
6.5(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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

March 24, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 4, 2026
No patch confirmed yet.
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

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2020723

Vendor Advisories for CVE-2026-3889(12)

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

Patch Availability(12)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatthunderbird-0:140.9.0-1.el8_42026-04-20redhat
redhatthunderbird-0:140.9.0-1.el9_02026-04-15redhat
redhatthunderbird-0:140.9.0-1.el8_62026-04-15redhat
redhatthunderbird-0:140.9.0-1.el8_82026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_42026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_62026-04-15redhat
redhatthunderbird-0:140.9.0-1.el8_22026-04-15redhat
redhatthunderbird-0:140.9.0-1.el10_02026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_22026-04-15redhat
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

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (306 versions)1:140.9.0esr-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
thunderbird1:102.11.0-1 ... 1:140.9.0esr-1~deb11u1 (191 versions)1:140.9.0esr-1~deb12u1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
thunderbird1:128.13.0esr-1 ... 1:140.9.0esr-1~deb11u1 (46 versions)1:140.9.0esr-1~deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
thunderbird1:128.13.0esr-1 ... 1:140.9.0esr-1~deb13u1 (48 versions)1:140.9.0esr-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 44× 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 170 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 13:53 UTCEPSS rescore
  4. 2026-09-01 04:39 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. 2026-08-23 00:19 UTCEPSS rescore
  11. 2026-08-21 23:49 UTCEPSS rescore
  12. 2026-08-20 22:55 UTCEPSS rescore
  13. 2026-08-19 17:03 UTCEPSS rescore
  14. 2026-08-18 13:48 UTCEPSS rescore
  15. 2026-08-17 13:47 UTCEPSS rescore
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 10:30 UTCEG score recompute
  18. 2026-08-16 10:30 UTCVendor advisory
  19. 2026-08-16 10:30 UTCGHSA enrichment
  20. 2026-08-16 02:14 UTCEPSS rescore
  21. 2026-08-15 01:30 UTCEPSS rescore
  22. 2026-08-14 06:48 UTCEG score recompute
  23. 2026-08-14 06:48 UTCVendor advisory
  24. 2026-08-14 06:48 UTCGHSA enrichment
  25. 2026-08-13 22:00 UTCEPSS rescore
Show 75 more
  1. 2026-08-12 22:42 UTCEG score recompute
  2. 2026-08-12 22:42 UTCVendor advisory
  3. 2026-08-12 22:42 UTCGHSA enrichment
  4. 2026-08-12 13:51 UTCEPSS rescore
  5. 2026-08-11 21:03 UTCEG score recompute
  6. 2026-08-11 21:03 UTCVendor advisory
  7. 2026-08-11 21:03 UTCGHSA enrichment
  8. 2026-08-11 13:43 UTCEPSS rescore
  9. 2026-08-11 00:00 UTCEPSS rescore
  10. 2026-08-10 08:03 UTCEG score recompute
  11. 2026-08-10 08:03 UTCVendor advisory
  12. 2026-08-10 08:03 UTCGHSA enrichment
  13. 2026-08-09 13:46 UTCEPSS rescore
  14. 2026-08-09 06:24 UTCVendor advisory
  15. 2026-08-09 06:24 UTCGHSA enrichment
  16. 2026-08-07 16:43 UTCEG score recompute
  17. 2026-08-07 16:43 UTCVendor advisory
  18. 2026-08-07 16:43 UTCGHSA enrichment
  19. 2026-08-06 13:46 UTCEPSS rescore
  20. 2026-08-06 01:09 UTCEG score recompute
  21. 2026-08-06 01:09 UTCVendor advisory
  22. 2026-08-06 01:09 UTCGHSA enrichment
  23. 2026-08-05 19:17 UTCEPSS rescore
  24. 2026-08-04 15:10 UTCEPSS rescore
  25. 2026-08-04 10:38 UTCEPSS rescore
  26. 2026-08-03 23:54 UTCEG score recompute
  27. 2026-08-03 23:54 UTCVendor advisory
  28. 2026-08-03 23:54 UTCGHSA enrichment
  29. 2026-08-03 10:36 UTCEPSS rescore
  30. 2026-08-02 15:43 UTCEG score recompute
  31. 2026-08-02 15:43 UTCVendor advisory
  32. 2026-08-02 15:43 UTCGHSA enrichment
  33. 2026-08-02 02:27 UTCEPSS rescore
  34. 2026-08-01 04:16 UTCEPSS rescore
  35. 2026-07-30 16:28 UTCEPSS rescore
  36. 2026-07-30 01:30 UTCEPSS rescore
  37. 2026-07-27 14:13 UTCEPSS rescore
  38. 2026-07-26 14:54 UTCEPSS rescore
  39. 2026-07-26 14:54 UTCEPSS rescore
  40. 2026-07-25 14:18 UTCEPSS rescore
  41. 2026-07-25 14:18 UTCEPSS rescore
  42. 2026-07-24 14:17 UTCEPSS rescore
  43. 2026-07-24 14:17 UTCEPSS rescore
  44. 2026-07-23 14:18 UTCEPSS rescore
  45. 2026-07-23 14:18 UTCEPSS rescore
  46. 2026-07-23 03:10 UTCEG score recompute
  47. 2026-07-22 14:08 UTCEPSS rescore
  48. 2026-07-21 15:24 UTCEPSS rescore
  49. 2026-07-20 17:08 UTCEPSS rescore
  50. 2026-07-19 14:31 UTCEPSS rescore
  51. 2026-07-19 02:29 UTCEPSS rescore
  52. 2026-07-18 10:04 UTCEPSS rescore
  53. 2026-07-16 17:03 UTCEPSS rescore
  54. 2026-07-15 16:57 UTCEPSS rescore
  55. 2026-07-15 16:57 UTCEPSS rescore
  56. 2026-07-15 02:00 UTCEPSS rescore
  57. 2026-07-13 22:30 UTCEPSS rescore
  58. 2026-07-13 06:13 UTCEPSS rescore
  59. 2026-07-13 06:13 UTCEPSS rescore
  60. 2026-07-12 05:46 UTCEPSS rescore
  61. 2026-07-09 19:10 UTCEPSS rescore
  62. 2026-07-08 15:15 UTCEPSS rescore
  63. 2026-07-07 13:46 UTCEPSS rescore
  64. 2026-07-06 16:27 UTCEPSS rescore
  65. 2026-07-06 16:27 UTCEPSS rescore
  66. 2026-07-06 02:23 UTCEPSS rescore
  67. 2026-07-06 02:23 UTCEPSS rescore
  68. 2026-07-05 02:30 UTCEPSS rescore
  69. 2026-07-04 06:31 UTCEPSS rescore
  70. 2026-07-01 15:06 UTCEPSS rescore
  71. 2026-06-30 23:22 UTCEPSS rescore
  72. 2026-06-29 14:06 UTCEPSS rescore
  73. 2026-06-28 14:07 UTCEPSS rescore
  74. 2026-06-28 04:56 UTCEPSS rescore
  75. 2026-06-27 03:08 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-3889?
CVE-2026-3889 is a medium vulnerability published on March 24, 2026. Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.
When was CVE-2026-3889 disclosed?
CVE-2026-3889 was first published in the National Vulnerability Database on March 24, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-3889 actively exploited?
CVE-2026-3889 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 89.9% of all scored CVEs.
What is the CVSS score of CVE-2026-3889?
CVE-2026-3889 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-3889?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-3889, 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-2026-3889

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