CVE-2026-73570: Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability

Q: How do I fix CVE-2026-73570?

zimbra collaboration suite: upgrade to 10.1.20. Exact commands for each OS are on this page.

Q: Is CVE-2026-73570 being exploited?

Yes. CVE-2026-73570 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

Q: What does CVE-2026-73570 affect?

CVE-2026-73570 affects zimbra collaboration suite. Severity is high (CVSS 8.9). 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 not

Q: How urgent is CVE-2026-73570?

Priority 91/100. High severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Public exploit reference; Remotely exploitable, no login, no user action

Patch now

HIGH 8.9EXPLOITEDREMOTEUPGRADE

CVE-2026-73570 is a high-severity flaw (CVSS 8.9) affecting zimbra collaboration suite, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Exploited in the wild (CISA KEV)
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.9 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	71.7% (top 1%)
CISA exploited list	Yes, fix due 2026-08-24
Weakness	CWE-78
Published	2026-08-13
Last modified	2026-08-24

Publisher (CNA): MITRE · Vendor: synacor

Last updated 2026-08-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-13 16:19 UTCPublished CVE record published
2026-08-21Exploited Added to the CISA Known Exploited Vulnerabilities list
2026-08-24Deadline CISA due date for US federal agencies to patch
2026-08-24 13:19 UTCUpdated Record last modified

synacor zimbra collaboration suite UPGRADE

Affected: < 10.1.20

Fixed in: 10.1.20

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy zimbra-collaboration-suite || rpm -q zimbra-collaboration-suite || zimbra-collaboration-suite --version

2. UPGRADE to 10.1.20 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade zimbra-collaboration-suite

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade zimbra-collaboration-suite

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora ELN · openbao · FIXED · 2.6.5-1.eln159 · FEDORA-2026-77adf886ae · source

sudo dnf upgrade --advisory=FEDORA-2026-77adf886ae

Fedora 46 · sugar-turtleart · FIXED · 220-16.fc46 · FEDORA-2026-b79483c788 · source

sudo dnf upgrade --advisory=FEDORA-2026-b79483c788

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: HORKimhab/CVE-2026-73570 (5 stars)
GitHub PoC: gabrielunknown/CVE-2026-73570 (4 stars)
GitHub PoC: jishino567/CVE-2026-73570 (3 stars)
Nuclei scan template: Zimbra Collaboration Suite < 10.1.20 - OS Command Injection

Advisories and coverage

Research and news

Elastic Security Labs: How CVE-2026-73570 turns a Zimbra log file into remote code execution 2026-10-23
Microsoft Security Blog: Unauthenticated command injection on internet-facing mail servers: tracking CVE-2026-73570 2026-09-30

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-73570?

zimbra collaboration suite: upgrade to 10.1.20. Exact commands for each OS are on this page.

Is CVE-2026-73570 being exploited?

Yes. CVE-2026-73570 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2026-73570 affect?

CVE-2026-73570 affects zimbra collaboration suite. Severity is high (CVSS 8.9). 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 not

How urgent is CVE-2026-73570?

Priority 91/100. High severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Zimbra vulnerabilities

Related CVEs

CVE-2026-73571 LOW 3.1 UPGRADE An authorization bypass vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.17 due to improper auth
CVE-2026-73572 MEDIUM 6.1 UPGRADE In Zimbra Collaboration (ZCS) before 10.1.17, a stored cross-site scripting (XSS) vulnerability exists in the
CVE-2026-73573 LOW 3.1 UPGRADE In Zimbra Collaboration (ZCS) before 10.1.17, a path traversal vulnerability exists in the Zimbra Briefcase do
CVE-2026-73574 LOW 3.1 UPGRADE In Zimbra Collaboration before 10.1.17, a local file inclusion (LFI) vulnerability exists in the Zimbra Classi
CVE-2026-73575 LOW 3.1 UPGRADE In Zimbra Collaboration (ZCS) before 10.1.17, a Cross-Site Request Forgery (CSRF) vulnerability exists in the

References

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