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Fencer Vulns
high 7.5

CVE-2026-84144 json

Internally found bugs fixed in Thunderbird 155 and Thunderbird ESR 153.2

published 2026-09-01 2 mo ago modified 2026-09-03 2 mo ago also EUVD-2026-69092

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

Internally found bugs present in Thunderbird 154 and Thunderbird ESR 153.1. 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 153.2, Thunderbird 155, and Thunderbird 153.2.

Patch / fix

  • mozilla firefox 153.2.0, 155.0.0
  • mozilla thunderbird 153.2.0, 155.0
  • MozillaThunderbird SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 153.2.0-150400.13.3.1
  • MozillaFirefox SLES for SAP applications 16.0, SLES 16.0 153.2.0-160000.1.1
  • mozilla-nss SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +11 more 3.125-150400.3.74.1
  • mozilla-nspr SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +11 more 4.39-150400.12.3.1
  • MozillaFirefox SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 153.2.0-150400.157.5.1
  • MozillaFirefox-branding-SLE SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 153-150400.14.3.1
  • mozilla-nss SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 3.125-58.147.1
  • mozilla-nspr SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 4.39-19.39.1

suse advisories SUSE-SU-2026:4268-1SUSE-SU-2026:23784-1SUSE-SU-2026:4156-1SUSE-SU-2026:4140-1

  • MozillaThunderbird openSUSE Tumbleweed 153.4.0-1.1
  • MozillaFirefox openSUSE Leap 16.0 153.2.0-160000.1.1
  • MozillaFirefox openSUSE Tumbleweed 155.0-1.1
  • firefox-esr openSUSE Tumbleweed 153.2.0-1.1

opensuse advisories openSUSE-SU-2026:12098-1openSUSE-SU-2026:21853-1openSUSE-SU-2026:11677-1openSUSE-SU-2026:11666-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-84144 updated cvss 7.5

firefox: thunderbird: Internally found bugs fixed in Firefox 155 and Firefox ESR 153.2

  • Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 firefox, thunderbird Red Hat Enterprise Linux 8 firefox, thunderbird Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird Red Hat Enterprise Linux 10 firefox, thunderbird, rhel10/firefox-flatpak, rhel10/thunderbird-flatpak
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Mozilla Firefox
  • Mozilla Thunderbird

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.