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CVE-2026-73570

8.9, high Known exploited

Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
8.9, high high CVSS v3.1
EPSS, next 30 days
72% higher than 99.4% of scored CVEs
Exploitation
Confirmed in the wild
Published
13 Aug 20262 months ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 21 Aug 2026. US federal agencies had to remediate by 24 Aug 2026, a deadline that has passed.

Required action. Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Description

A remote code execution vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.20 when the optional zimbra-snmp package is installed and SNMP notifications are enabled. Due to improper sanitization of untrusted input during SNMP notification processing, an unauthenticated attacker can send specially crafted SMTP requests that may result in execution of arbitrary operating system commands as the Zimbra user.

Details

Vendor
Synacor
Product
Collaboration
Weakness
CWE-78 (opens in a new tab)
Status
Analyzed
Updated
24 Aug 2026
Assigner
cve@mitre.org

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

References 4

Advisories 3

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Synacor CVEs

Every Synacor CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2025-66376 Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability KEV EPSS 20% 6.1, medium
  • CVE-2025-68645 Synacor Zimbra Collaboration Suite (ZCS) PHP Remote File Inclusion Vulnerability KEV EPSS 49% 8.8, high
  • CVE-2025-48700 Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability KEV EPSS 2% 6.1, medium
  • CVE-2025-27915 Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability KEV EPSS 4% 5.4, medium
  • CVE-2024-45519 Synacor Zimbra Collaboration Suite (ZCS) Command Execution Vulnerability KEV EPSS 100% 9.8, critical
  • CVE-2024-27443 Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability KEV EPSS 25% 6.1, medium
  • CVE-2023-37580 Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability KEV EPSS 49% 6.1, medium
  • CVE-2023-34192 Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability KEV EPSS 77% 9, critical

Beyond this page

Is CVE-2026-73570 in your network?

This page tells you how dangerous CVE-2026-73570 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2026-73570 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2026-73570 comes with the devices to patch.

    Learn more about EXYS7600 OCELOT

  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.