CVE-2026-84637

criticalpriority · track · 0EPSS 0.006 · 50 %ileDEUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.63% (50th) EPSS

CVSS 9.8 · critical

Is it mine?

24 products

Check your exposure

Who says so?

1 sources

cert_bund

EPSS · scored 2026-10-26

Malicious calendar invitations could use file URI attachments to launch local or network-hosted executables on Windows, bypassing Thunderbird's normal executable attachment protections. With the new invitation display enabled, the attachment could also appear under a misleading filename. This vulnerability was fixed in Thunderbird 154 and Thunderbird 153.2.

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondaryexploitability 3.9 · impact 5.9

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-434US

affected products (24)

Products and version ranges known to be affected.

Amazon Linux 2all versionscert_bundDEcpe:/o:amazon:linux_2:-
Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
IGEL OSall versionscert_bundDEcpe:/o:igel:os:-
Oracle Linuxall versionscert_bundDEcpe:/o:oracle:linux:-
RESF Rocky Linuxall versionscert_bundDEcpe:/o:resf:rocky_linux:-
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
SUSE Linuxall versionscert_bundDEcpe:/o:suse:suse_linux:-
SUSE openSUSEall versionscert_bundDEcpe:/o:suse:opensuse:-
Mozilla Firefox< 155cert_bundDE
Mozilla Firefox ESR< 115.40cert_bundDE
Mozilla Firefox ESR< 140.15cert_bundDE
Mozilla Firefox ESR< 153.2cert_bundDE
Mozilla Mozilla Firefox <155< 155cert_bundDE
Mozilla Mozilla Firefox ESR <115.40< 115.40cert_bundDE
Mozilla Mozilla Firefox ESR <140.15< 140.15cert_bundDE
Mozilla Mozilla Firefox ESR <153.2< 153.2cert_bundDE
Mozilla Mozilla Thunderbird <140.15< 140.15cert_bundDE
Mozilla Mozilla Thunderbird <153.2< 153.2cert_bundDE
Mozilla Mozilla Thunderbird <155< 155cert_bundDE
Mozilla Thunderbird< 140.15cert_bundDE

showing 20 of 24

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-3132Mozilla Firefox und Thunderbird: Mehrere SchwachstellenDeutsch2026-09-01csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Mozilla Firefox und Thunderbird ausnutzen, um Berechtigungen zu erweitern, Sicherheitsmaßnahmen zu umgehen, sensible Informationen offenzulegen, Daten zu manipulieren, Spoofing-Angriffe durchzuführen, möglicherweise durch Speicherbeschädigungen beliebigen Code auszuführen oder Denial-of-Service-Zustände herbeizuführen.

sources

Which sources assert this record, and when.

cert_bund NVD CVE.org MITRE

published 2026-09-01modified 2026-09-03

references (3) nvd

External citations — patches, advisories, analysis.

https://bugzilla.mozilla.org/show_bug.cgi?id=2043878Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-78/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-88/Vendor Advisory

scry

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