CVE-2026-4371

HIGHPre-NVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

Score 7.4 from GitHub Security Advisory (severity: HIGH) published 2026-03-24. NVD baseline CVSS 7.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.4
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.4Exploit: NoneExposed: 0

A fix is available — apply it.

A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

CVSS v3
7.4
EG Score
7.4(medium)
EPSS
28.3%
KEV
Not listed

Published

March 24, 2026

Last Modified

July 15, 2026

Advisory Details (10)

Auto-updated Jul 15, 2026
Patch available. Sources: redhat.
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions.

https://access.redhat.com/errata/RHSA-2026:8287
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions.

https://access.redhat.com/errata/RHSA-2026:8286
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.2 Advanced Update Support.

https://access.redhat.com/errata/RHSA-2026:8285
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.6 Extended Update Support.

https://access.redhat.com/errata/RHSA-2026:8284
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:6917
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:6342
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:6188
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=2023493

Vendor Advisories for CVE-2026-4371(13)

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.el8_82026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_22026-04-15redhat
redhatthunderbird-0:140.9.0-1.el9_02026-04-15redhat
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.el8_62026-04-15redhat
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.

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 37× 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 101 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-4371?
CVE-2026-4371 is a high vulnerability published on March 24, 2026. A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking…
When was CVE-2026-4371 disclosed?
CVE-2026-4371 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-2026-4371 actively exploited?
CVE-2026-4371 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 28.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-4371?
CVE-2026-4371 has a CVSS v3.1 base score of 7.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-4371?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4371, 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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