CVE-2026-84120

mediumpriority · track · 0EPSS 0.002 · 12 %ileDEUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.22% (12th) EPSS

CVSS 5.4 · medium

Is it mine?

29 products

Check your exposure

Who says so?

1 sources

cert_bund

EPSS · scored 2026-10-27

Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

cvss

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

5.4

010

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

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:Nsecondaryexploitability 2.8 · impact 2.5

v3.15mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)

ssvc

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

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-416US

affected products (29)

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 29

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 2026-09-02

references (8) nvd

External citations — patches, advisories, analysis.

https://bugzilla.mozilla.org/show_bug.cgi?id=2058911Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-82/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-83/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-84/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-85/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-86/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-87/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-88/Vendor Advisory

scry

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