Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
- https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/
FAQ
What is CVE-2026-93640?
CVE-2026-93640 is a vulnerability with a CVSS score of 7.8 (HIGH). 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 su...
How severe is CVE-2026-93640?
CVE-2026-93640 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-93640?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.