What is CVE-2026-73570?

CVE-2026-73570 is Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability. The supplied enrichment data classifies it as Remote Code Exec mapped to CWE-78 OS Command Injection.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

9 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, EDR process telemetry, host service logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-73570 using CVSS 8.9, EPSS 21%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVhighRemote Code Execpublic exploit

CVE-2026-73570

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

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2026-73570 in CISA KEV with 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.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

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.

Published Aug 13, 2026Updated Aug 24, 2026Sources: NVD, Zimbra (CNA), CISA, FIRST EPSS, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Aug 21, 2026

EPSS

21%

ahead of 97% of scored CVEs

Affects

Zimbra

Collaboration

CVSS base

8.9

high

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade Collaboration to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

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.

Federal deadline Aug 24, 2026 — passed 8 days ago

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Zimbra	Collaboration	0 to < 10.1.20	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

Low

Confidentiality

High

Integrity

High

Scope

Changed

Attack Complexity

High

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
8.9	CVSS 3.1	high	2.2	6	MITRE (CNA), Zimbra (CNA)

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

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Execute Unauthorized Code or Commands
DoS: Crash, Exit, or Restart
Read Files or Directories
Modify Files or Directories

Mitigation: If at all possible, use library calls rather than external processes to recreate the desired functionality.

Weakness & attack patterns

CWE-78OS Command Injection

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-15 · Command DelimitersCAPEC-88 · OS Command InjectionCAPEC-43 · Exploiting Multiple Input Interpretation LayersCAPEC-108 · Command Line Execution through SQL InjectionCAPEC-6 · Argument Injection

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Aug 21, 2026

Federal deadline

Aug 24, 2026

passed 8 days ago

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1 of the 5 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

35 more posts on this CVEShowing 5 of 40 · Who is discussing this CVE, and how loudlyUnlock free

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Prioritize edge telemetry for network-reachable Collaboration.
Monitor for scanner or exploit-pattern traffic after 9 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPSEDR process telemetryhost service logs

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

ip185.209.228.16266
Blocklist.de-Firehol-iMAP · Aug 23, 2023
urlhttp://147.182.224.216/zed89
Maltiverse URL List · Aug 26, 2026

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Cve is exploited gabrielunknown/CVE-2026-73570
Aug 26, 2026 · SOCRadar CTI
Cve is exploited jishino567/CVE-2026-73570
Aug 25, 2026 · SOCRadar CTI
Added · CVSS 3.1 8.9 (AV:N)
Aug 24, 2026 · NVD
Cve is exploited BiuTrap/CVE-2026-73570
Aug 24, 2026 · SOCRadar CTI
Added to CISA KEV catalog
Aug 21, 2026 · CISA
Initial · CVE published
Aug 13, 2026 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

11×TweetsAug 20, 2026 – Aug 29, 2026 · SOCRadar CTI
9×SvrsAug 20, 2026 – Aug 29, 2026 · SOCRadar CTI
6×Github ReposAug 21, 2026 – Aug 28, 2026 · SOCRadar CTI
5×ModifiedAug 13, 2026 – Aug 22, 2026 · SOCRadar CTI
2×TelegramAug 14, 2026 – Aug 26, 2026 · SOCRadar CTI
1×CVE appeared in the Cve Trends.Aug 21, 2026 · SOCRadar CTI

References

8 on the record

wiki.zimbra.com/wiki/Security_Center
Release Notes, NIST
wiki.zimbra.com/wiki/Zimbra_Security_Advisories
Vendor Advisory, NIST
moje.cert.pl/komunikaty/2026/145/aktywnie-wykorzystywana-podatnosc-w-zimbra-collaboration-suite/
Third Party Advisory, NIST
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-73570
US Government Resource, NIST
blog.zimbra.com/2026/07/patch-release-update-zimbra-10-1-20/
Vendor Advisory
www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
US Government Resource
www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
US Government Resource
nvd.nist.gov/vuln/detail/CVE-2026-73570
Vendor Advisory

Coverage

19 stories from the feeds we poll

14 more reports on this CVEShowing 5 of 19 · Vendor research and security press coverageUnlock free

Elsewhere on this site

Zimbraevery CVE for this vendor
August 2026what else CISA listed
Remote Code Execsame class
CWE-78other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

Only the 2 indicator(s) reported for this CVE are available; no packet-level or host-forensic artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-73570 is Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability, a high vulnerability affecting Collaboration from Zimbra. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 9 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 8.9 describes technical severity, while EPSS 21% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.