CVE-2026-14899

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH 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(high)
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 (218 versions)1:140.13.0esr-1—
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 ... 1:153.0.1esr-1 (84 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 44× in last 7d / 153× 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 153 total refreshes for this CVE.

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

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 80.2% 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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