Cyber Resilience

CVE-2026-73570

RCE in Synacor Zimbra Collaboration Suite ≤ 10.1.20

CISA KEVActive ExploitationEUVD ExploitedRCECommand Injection
Published
13 August 2026
Modified
24 August 2026
KEV Added
21 August 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
EPSS Score 0.32 98th percentile
Risk Priority 89 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-73570 is a high-severity OS Command Injection (CWE-78) vulnerability in Synacor Zimbra Collaboration Suite. Its CVSS base score is 8.9 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

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…

more

specially crafted SMTP requests that may result in execution of arbitrary operating system commands as the Zimbra user.

CWE(s)
CWE-78
KEV Date Added
21 August 2026

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
attack.mitre.org →
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
attack.mitre.org →
T1059.003 Windows Command Shell Execution
Adversaries may abuse the Windows command shell for execution.
attack.mitre.org →
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-45519Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2022-27924Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2022-24682Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2022-27925Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2022-41352Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2019-9621Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2022-37042Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2020-7796Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2019-9670Same product: Synacor Zimbra Collaboration Suiteboth on KEV
CVE-2022-27926Same product: Synacor Zimbra Collaboration Suiteboth on KEV

Affected Assets

synacor
zimbra collaboration suite
≤ 10.1.20

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.2.5
  • V1.2.8
  • V15.2.5

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover missing or incorrect command sanitization during development.

SI-10 Information Input Validation good match

Input validation directly neutralizes or rejects special characters that would otherwise alter OS command structure.

AC-6 Least Privilege partial match

Least privilege reduces the permissions available to any process that could be subverted by injected commands.

CM-7 Least Functionality partial match

Least functionality restricts available OS commands and interpreters, limiting the blast radius of injection.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles require proper neutralization of untrusted input before command construction.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.

PR.PS-02 partial match
prevents

Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.

References