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TI-2026-79899 Aliases CVE-2026-50056GHSA-ww99-8662-82q8

Local root escalation in Zimbra Collaboration Suite launcher

Priority LOW 36CWE-88Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-88.

Summary

Zimbra Collaboration Suite (ZCS) through 10.1.21 is affected, including 10.1.16. The zmmailboxdmgr launcher accepts JVM arguments that are not adequately restricted, so a local user with the zimbra account can run arbitrary commands as root. The flaw is an improper neutralization of argument delimiters in a command (CWE-88). Exploitation requires local command execution as zimbra on a mailbox server and interrupts mailboxd during the restart.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

Description from the CNA

A local privilege escalation vulnerability in the zmmailboxdmgr launcher of Zimbra Collaboration Suite (ZCS) allows the Unix zimbra account to execute arbitrary commands as root. The passwordless sudo interface accepts JVM arguments that are not adequately restricted. An attacker can postpone Jetty's privilege drop, register an OnOutOfMemoryError command and force heap exhaustion during startup, causing the command to execute while the JVM still runs as root. Exploitation requires local command execution as zimbra on a mailbox server and interrupts mailboxd during the malicious restart. ZCS 10.1.16 and 10.1.21 are affected.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00344 28th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ZimbraZimbra Collaboration Suiteup to 10.1.21—No fix listedCNA
  • Zimbra Collaboration Suite VendorZimbra Affected up to 10.1.21 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*——Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:* Versions — — ·Synacor

Remediation

The sources list no fixed version for Zimbra Collaboration Suite.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

Timeline

  1. 2026-10-23 Threatist record created from CVE-2026-50056
  2. 2026-10-23 Alias added: GHSA-ww99-8662-82q8
  3. 2026-10-24 CISA SSVC decision points changed
  4. 2026-10-24 Priority changed: MEDIUM → LOW
  5. 2026-10-29 CISA SSVC decision points changed

References

Advisory 1

Other 1

  • TI-2026-51660 OS command injection in Zimbra Collaboration KEVCVSS 3.1HIGH 8.9
  • TI-2025-40820 Cross-site scripting in Zimbra Collaboration KEVCVSS 3.1HIGH 7.2
  • TI-2024-18266 An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. KEVCVSS 3.1MEDIUM 6.1
  • TI-2024-30553 An issue was discovered in Zimbra Collaboration (ZCS) 10.1.x before 10.1.1, 10.0.x before… CVSS 3.1HIGH 8.8
  • TI-2022-13998 Zimbra Collaboration Open Source 8.8.15 does not encrypt the initial-login randomly… CVSS 3.1CRITICAL 9.8
  • TI-2026-63080 Path traversal in Zimbra Collaboration Suite CVSS 3.1CRITICAL 9.8
See all 94 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences