Mozilla Produkte (Thunderbird, Firefox ESR und Firefox): Mehrere Schwachstellen
WID-SEC-2026-4064 · first 21.10.2026 · updated 29.10.2026 · CVSS 8,6
What it is about
Thunderbird ist ein Open Source E-Mail Client. Firefox ist ein Open Source Web Browser. ESR ist die Variante mit verlängertem Support. Firefox ist ein Open Source Web Browser. Ein Angreifer kann mehrere Schwachstellen in Mozilla Thunderbird, Mozilla Firefox ESR und Mozilla Firefox ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen und um Daten zu manipulieren.
Under what conditions?
The BSI does not name any particular preconditions. Exploitable remotely according to the BSI.
What can happen in the worst case
An attacker could use the vulnerability to
- Sicherheitsvorkehrungen zu umgehen
- einen Denial of Service Angriff durchzuführen
- Informationen offenzulegen
- Daten zu manipulieren
Am I affected?
Affected according to the BSI:
- Debian Linux
- Amazon Linux 2
- Broadcom Fabric OS
- SUSE Linux
- SUSE openSUSE
- Oracle Linux
- Mozilla Thunderbird <153.5.1
- Mozilla Thunderbird <158.0.1
- Mozilla Firefox ESR <115.43.1
- Mozilla Firefox ESR <153.5.1
- Mozilla Firefox <158.0.1
- Mozilla Firefox Android <158.0.2
The installed version is usually shown under “Help → About” or in the device’s admin interface.
What helps?
Update to at least:
- Mozilla Thunderbird 153.5.1
- Mozilla Thunderbird 158.0.1
- Mozilla Firefox ESR 115.43.1
- Mozilla Firefox ESR 153.5.1
- Mozilla Firefox 158.0.1
- Mozilla Firefox Android 158.0.2
Is the vulnerability already being exploited?
None of the CVEs is in the CISA catalogue of exploited vulnerabilities. That does not mean there are no attacks, only that none are documented.
Information and sources
- Original BSI advisory (WID)
- Mozilla Security Advisory mfsa2026-111 vom 2026-10-20 www.mozilla.org
- Mozilla Security Advisory mfsa2026-112 vom 2026-10-20 www.mozilla.org
- Mozilla Security Advisory mfsa2026-113 vom 2026-10-20 www.mozilla.org
- Mozilla Security Advisory mfsa2026-114 vom 2026-10-20 www.mozilla.org
- Mozilla Security Advisory mfsa2026-115 vom 2026-10-20 www.mozilla.org
- Debian Security Advisory DSA-6573 vom 2026-10-21 security-tracker.debian.org
- Oracle Linux Security Advisory ELSA-2026-500450 vom 2026-10-21 linux.oracle.com
- Mozilla Security Advisory MFSA2026-116 vom 2026-10-21 www.mozilla.org
- Oracle Linux Security Advisory ELSA-2026-500449 vom 2026-10-21 linux.oracle.com
- Debian Security Advisory DLA-4847 vom 2026-10-21 lists.debian.org
- Oracle Linux Security Advisory ELSA-2026-500451 vom 2026-10-21 linux.oracle.com
- Oracle Linux Security Advisory ELSA-2026-500496 vom 2026-10-23 linux.oracle.com
- Amazon Linux Security Advisory ALAS2-2026-4037 vom 2026-10-25 alas.aws.amazon.com
- Amazon Linux Security Advisory ALAS2FIREFOX-2026-068 vom 2026-10-25 alas.aws.amazon.com
- Debian Security Advisory DSA-6585 vom 2026-10-26 lists.debian.org
- openSUSE Security Update OPENSUSE-SU-2026:22159-1 vom 2026-10-24 lists.opensuse.org
- Debian Security Advisory DLA-4863 vom 2026-10-26 lists.debian.org
- Brocade Security Advisory vom 2026-10-27 support.broadcom.com
- SUSE Security Update SUSE-SU-2026:24412-1 vom 2026-10-29 lists.suse.com
CVE: CVE-2026-113399, CVE-2026-113400, CVE-2026-113401, CVE-2026-113470, CVE-2026-113866, CVE-2026-113867, CVE-2026-113868, CVE-2026-113869
Source: BSI warning and information service (CERT-Bund); CISA. The assessment of the conditions is my reading of the BSI text; the external pages are in their original language.