CVE-2026-14899

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-22. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

A fix is available — apply it.

The code to parse MIME headers for display when forwarding a message (if the setting to view all headers was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in Thunderbird 153 and Thunderbird 140.13.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

July 22, 2026

Last Modified

August 12, 2026

Advisory Details (3)

Auto-updated Jul 27, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

Security Vulnerabilities fixed in Thunderbird 140.13 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-72/
generic

Security Vulnerabilities fixed in Thunderbird 153 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-71/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2046137

Vendor Advisories for CVE-2026-14899(11)

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

Patch Availability(10)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatthunderbird-0:140.13.0-1.el8_42026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_22026-08-11redhat
redhatthunderbird-0:140.13.0-1.el8_82026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_42026-08-11redhat
redhatthunderbird-0:140.13.0-1.el10_02026-08-11redhat
redhatthunderbird-0:140.13.0-1.el8_62026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_62026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_82026-08-04redhat
redhatthunderbird-0:140.13.0-1.el8_102026-08-04redhat
redhatthunderbird-0:140.13.0-1.el10_22026-08-03redhat

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 (334 versions)1:140.13.0esr-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (220 versions)1:140.13.0esr-2~deb12u1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (76 versions)1:140.13.0esr-2~deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (73 versions)1:140.13.0esr-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 27× in last 7d / 122× 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 273 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-14899?
CVE-2026-14899 is a high vulnerability published on July 22, 2026. The code to parse MIME headers for display when forwarding a message (if the setting to view all headers was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in…
When was CVE-2026-14899 disclosed?
CVE-2026-14899 was first published in the National Vulnerability Database on July 22, 2026, with the most recent update on August 12, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-14899 actively exploited?
CVE-2026-14899 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 80.0% of all scored CVEs.
What is the CVSS score of CVE-2026-14899?
CVE-2026-14899 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-14899?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-14899, 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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