Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15 (Mozilla Firefox)

CVE-2026-84143
CRITICAL 9.8

At a glance

Source
NVD
EPSS
EPSS 0.38 % · percentile 32 ()
State
PUBLISHED
Published
Updated
Assigner
mozilla
NVD status
Modified

Description

Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Weaknesses (CWE)

  • CWE-200 — Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Scores

VersionScoreVectorScored by
CVSS 3.1CRITICAL 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCISA-ADP
CVSS 3.1CRITICAL 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HNVD · nvd@nist.gov (Primary)
CVSS 3.1CRITICAL 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HNVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Mozilla · Firefoxunaffected 140.15 ≤ 140.* ; unaffected 153.2 ≤ 153.* ; unaffected 155 ≤ *
Mozilla · Thunderbirdunaffected 140.15 ≤ 140.* ; unaffected 153.2 ≤ 153.* ; unaffected 155 ≤ *

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD