Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability
Zimbra — Collaboration
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.
8.9
20.5%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
- Published
- Aug 13, 2026
- Modified
- Aug 24, 2026
- Added to KEV
- Aug 21, 2026
- Federal patch due
- Aug 24, 2026
CISA 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.
Weakness classification
Affected packages
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2026-73570, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2026-73570 were found at last check. Absence here is not proof no exploit exists — see the references below for vendor advisories and write-ups.
References
How this class of flaw gets exploited
Frequently asked questions
What is CVE-2026-73570?
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.
How severe is CVE-2026-73570?
CVE-2026-73570 has a CVSS base score of 8.9 out of 10 (CVSS 3.1).
Is CVE-2026-73570 actively exploited in the wild?
Yes. CVE-2026-73570 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Aug 21, 2026, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2026-73570?
20.5% - meaning FIRST.org's EPSS model estimates a 20.5% probability this vulnerability will be exploited in the wild within 30 days (97% percentile among all scored CVEs).
What type of vulnerability is CVE-2026-73570?
CVE-2026-73570 is classified under CWE-78 (CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')).
Cross-checked against
Impactr finds and proves whether CVE-2026-73570 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.