CVE WatchAug 24, 2026

CVE-2026-73570

Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability

CVSS

8.9

High

EPSS

76.6%

p100

KEV

YES

Aug 21, 2026

Exploit Today

0-100

Published: Aug 13, 2026 · Last modified: Aug 24, 2026 · CWE-78

EPSS · 30d

71.7%EPSS · 30 days76.6%

2026-10-152026-11-11

KEV catalog record

Product

Synacor / Zimbra Collaboration Suite (ZCS)

Vulnerability

Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability

Added to KEV

Aug 21, 2026

Remediate by

Aug 24, 2026

Known ransomware use

Summary description

Zimbra Collaboration Suite (ZCS) contains an OS command injection vulnerability which could allow an unauthenticated attacker to send specially crafted SMTP requests that may result in execution of arbitrary operating system commands as the Zimbra user.

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.

Notes

https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories ; https://blog.zimbra.com/2026/07/patch-release-update-zimbra-10-1-20/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-73570

Technical 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.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-1240138.8 HIG

—

———XWEB EVO 5.6.2 through 5.8.8 contains an authenticated OS command injection vulnerability in the api.lua import_preconfiguration and restore actions, where server_url and related server credential fields are concatenated unescaped into a root curl command executed via io.popen. Attackers can inject malicious shell commands through these unfiltered parameters to achieve arbitrary command execution with root privileges on the underlying system. This product line reached it's end of service date in March 2026.13h CVE-2026-1240109.8 CRI

—

———XWEB EVO before 5.6.2 contains a command injection vulnerability that allows unauthenticated remote attackers to execute arbitrary commands as root by exploiting the setuid-root CGI xwconsole.cgi. Attackers can supply malicious input through the sh parameter, which is passed unsanitized to popen(), to achieve full system compromise. This product line reached it's end of service date in March 2026.13h CVE-2026-1240097.2 HIG

—

———XWEB EVO 5.2.3 through 5.8.8 contains an authenticated OS command injection vulnerability that allows authenticated attackers to execute arbitrary commands as root by injecting shell metacharacters into the output device path parameter processed by backup.lua. Attackers can exploit the unescaped concatenation into mount, unzip, and related shell commands run via the wlua interpreter, including through the setuid xwbackup.cgi and xwrestore.cgi interfaces, to achieve full system compromise. This product line reached it's end of service date in March 2026.13h CVE-2026-1240087.2 HIG

—

———XWEB EVO 5.2.3 through 5.8.8 contains an authenticated OS command injection vulnerability in the devices.lua template handling, which allows authenticated attackers to execute arbitrary commands by injecting unescaped template source into unzip and related shell commands. Attackers can exploit this flaw through the wlua interpreter to execute arbitrary commands with root privileges on the affected device. This product line reached it's end of service date in March 2026.13h CVE-2026-1240078.1 HIG

—

———XWEB EVO before 5.6.2 contains a pre-authentication OS command injection vulnerability that allows unauthenticated remote attackers to execute arbitrary commands by injecting shell metacharacters into the password field. Attackers can exploit the unescaped interpolation of the password value into the hashpass invocation within login.lua, cleanout.lua, and api.lua to achieve root-level command execution via the setuid wlua interpreter. This product line reached it's end of service date in March 2026.8h CVE-2026-1240029.8 CRI

—

———XWEB EVO versions 5.2.3 through before 5.7.0 contains a pre-authentication OS command injection vulnerability that allows unauthenticated remote attackers to execute arbitrary OS commands by injecting shell metacharacters into the username field of login.lua, cleanout.lua, or api.lua before the password check occurs. Attackers can exploit this flaw combined with the setuid-root wlua interpreter to execute commands with root privileges, achieving full system compromise. This product line reached it's end of service date in March 2026.13h