Vulnerability · Published Oct 23, 2026 · Assigned by rapid7
CVE-2026-93640Zimbra Collaboration Suite Local Privilege Escalation via Unrestricted zmunbound Sudo Configuration
High 7.8
In plain English
A high-severity incorrect permission assignment in Zimbra Collaboration Suite from Zimbra. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).
Official description
A local privilege escalation vulnerability in the optional dnscache package of Zimbra Collaboration Suite (ZCS) allows the Unix zimbra account to access files with root privileges. The passwordless sudo policy permits arbitrary arguments to zmunbound, whose wrapper forwards them to Unbound without restricting the configuration path. An attacker can supply a configuration that retains root privileges and disables the chroot. Include directives expose root-readable file contents through parser errors, while an attacker-selected logfile path creates a root-owned file or appends Unbound log records to an existing file. This can disclose password hashes and private keys and corrupt privileged configuration files, preventing affected services from starting with the modified configuration. The affected configuration is present in ZCS 10.1.16 and 10.1.21 dnscache packages.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Zimbra | Zimbra Collaboration Suite | 0 – through 10.1.21 |
Weakness: CWE-732 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H