Uninitialized memory in MIME parsing (Mozilla Thunderbird)

CVE-2026-84639
CRITICAL 9.1

At a glance

Source
NVD
EPSS
EPSS 0.32 % · percentile 25 ()
State
PUBLISHED
Published
Updated
Assigner
mozilla
NVD status
Analyzed

Description

Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Weaknesses (CWE)

  • CWE-457 — Use of Uninitialized Variable

References

Scores

VersionScoreVectorScored by
CVSS 3.1CRITICAL 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HCISA-ADP
CVSS 3.1CRITICAL 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HNVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
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