[UPDATE] [high] Synacor Zimbra: Multiple vulnerabilities

highCVE-2026-73571 CVE-2026-73572 CVE-2026-73573 CVE-2026-73574 CVE-2026-73575 CVE-2026-73576

An attacker can exploit multiple vulnerabilities in Synacor Zimbra to disclose information, perform a cross-site scripting attack and bypass security measures.

CSIRTS triage

vendor: Synacor product: Zimbra Information disclosure Cross-site scripting Authentication bypass

What: Multiple vulnerabilities in Zimbra allow information disclosure, cross-site scripting, and security bypass attacks.
Who is affected: All Zimbra deployments are potentially affected.
Urgency: High severity; no active exploitation reported but multiple attack vectors present warrant rapid remediation.
Action: Apply vendor security patches addressing CVE-2026-73571 through CVE-2026-73576 immediately.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CERT-Bund (BSI) Security Advisories (DE · national-cert · site)
Severity: high
Published: 2026-08-14
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-1735

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-735710.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-735720.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-735730.25% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 17% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-735740.20% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 10% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-735750.11% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 2% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-735760.19% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 9% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-73571	coverage & exploitation status	NVD · CVE.org
CVE-2026-73572	coverage & exploitation status	NVD · CVE.org
CVE-2026-73573	coverage & exploitation status	NVD · CVE.org
CVE-2026-73574	coverage & exploitation status	NVD · CVE.org
CVE-2026-73575	coverage & exploitation status	NVD · CVE.org
CVE-2026-73576	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Synacor Zimbra

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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