Auth bypass in Zimbra Collaboration Suite

CVE-2026-50055

A policy-enforcement flaw in Zimbra Collaboration Suite allows an authenticated user to bypass disabled mail forwarding by using a Sieve notify action to send copies of email content and headers to an arbitrary address.

Vulnerability class: Broken Access Control

Published .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-50055?
CVE-2026-50055 is a medium-severity vulnerability in Zimbra Collaboration Suite, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-10-08.
How severe is CVE-2026-50055?
Medium severity. CVSS v3 base score is 6.5 out of 10.