CVE-2026-50055 Zimbra Collaboration Suite Sieve Notify Filter Action Bypasses Mail Forwarding Restriction via Variable Expansion
Authenticated users can bypass mail forwarding restrictions using Sieve notify actions to exfiltrate email content and headers to arbitrary addresses.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-50055?
CVE-2026-50055 is a medium-severity vulnerability in Zimbra Collaboration Suite, published on 8 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-863
Which versions are affected by CVE-2026-50055?
How do I fix CVE-2026-50055?
No fix has been published for CVE-2026-50055 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-50055 being exploited?
There is no known exploitation of CVE-2026-50055 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-p88h-r6ph-r7j6.