Synacor Zimbra: Mehrere Schwachstellen
WID-SEC-2025-2911 · first 23.12.2025 · updated 19.03.2026 · CVSS 8,8
What it is about
Zimbra ist eine Groupware-Lösung, die E-Mail, Kalender und Aufgabenverwaltung bietet. Ein Angreifer kann mehrere Schwachstellen in Synacor Zimbra ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen, um Sicherheitsvorkehrungen zu umgehen, und um beliebigen Programmcode auszuführen.
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
- einen Cross-Site Scripting Angriff durchzuführen
- Sicherheitsvorkehrungen zu umgehen
- beliebigen Programmcode auszuführen
Am I affected?
Affected according to the BSI:
- Synacor Zimbra <10.1.13
- Synacor Zimbra <10.0.18
The installed version is usually shown under “Help → About” or in the device’s admin interface.
What helps?
Update to at least:
- Synacor Zimbra 10.1.13
- Synacor Zimbra 10.0.18
Is the vulnerability already being exploited?
- CVE-2025-66376: exploited in the wild according to CISA, in the catalogue since 18.03.2026.
- CVE-2025-68645: exploited in the wild according to CISA, in the catalogue since 22.01.2026.
- According to a CISA advisory, used by actors from Russia: Russian State-Supported Cyber Actors Conduct Phishing Campaign Targeting Users of Zimbra Collaboration Suite (07/2026)
Information and sources
- Original BSI advisory (WID)
- Zimbra Security Advisory vom 2025-12-22 wiki.zimbra.com
- NIST Vulnerability Database vom 2025-12-22 nvd.nist.gov
- NIST Vulnerability Database vom 2025-12-22 nvd.nist.gov
- PoC auf GitHub vom 2026-01-01 github.com
- CISA Known Exploited Vulnerabilities Catalog vom 2026-03-18 www.cisa.gov
CVE: CVE-2025-66376, CVE-2025-67809, CVE-2025-68645
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.