CVE-2026-50056: Zimbra Collaboration Suite · Argument Injection
Affects Zimbra Collaboration SuiteSource CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 17:30 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-23.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| ZimbraZimbra Collaboration Suite | Affected
| Fixed in– |
AI-suggested
Until a fix is available, restrict local access to the zimbra user and mailbox servers to trusted administrators only to reduce risk.
Description
CVE-2026-50056 is a local privilege escalation vulnerability in the zmmailboxdmgr launcher of Zimbra Collaboration Suite (ZCS). It allows the Unix zimbra account to execute arbitrary commands as root by exploiting a passwordless sudo interface that accepts unrestricted JVM arguments. The attack involves postponing Jetty's privilege drop and forcing heap exhaustion during startup to execute commands with root privileges. This requires local access as the zimbra user on a mailbox server and interrupts mailboxd during a malicious restart. Versions up to and including 10.1.21 are affected.