CVE-2026-93639 A missing authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows a delegated administrator with no explicit administrative g
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-93639?
CVE-2026-93639 is a high-severity vulnerability in Zimbra Collaboration Suite, published on 23 Oct 2026.
Official description
A missing authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows a delegated administrator with no explicit administrative grants to overwrite global Zimlet configuration through ConfigureZimletRequest. The uploaded configuration can also add an attacker-controlled domain to the proxy allowlist of the default class of service. If a signed-in user in that class opens a crafted /service/proxy URL, Zimbra serves attacker-controlled HTML under its own origin. The resulting JavaScript can read mailbox data and perform authenticated actions as the victim. Exploitation requires a delegated-administrator account and access to the admin SOAP service; the browser compromise additionally requires the victim to open the crafted URL. ZCS 10.1.16 and 10.1.20 are affected.
Weakness: CWE-862
Which versions are affected by CVE-2026-93639?
How do I fix CVE-2026-93639?
No fix has been published for CVE-2026-93639 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-93639 being exploited?
There is no known exploitation of CVE-2026-93639 in the wild and no public exploit code.
Sources
Also known as GHSA-q3fj-jg2r-pp4p.