CVE-2026-39355 Missing authorization in genealogy

Critical 10.0 Published 7 Apr 2026 Updated 8 Apr 2026

An authenticated user can hijack any team by transferring ownership, gaining unrestricted access to associated genealogy data.

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-2026-39355?

CVE-2026-39355 is a critical missing authorization vulnerability in MGeurts genealogy, published on 7 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Genealogy is a family tree PHP application. Prior to 5.9.1, a critical broken access control vulnerability in the genealogy application allows any authenticated user to transfer ownership of arbitrary non-personal teams to themselves. This enables complete takeover of other users’ team workspaces and unrestricted access to all genealogy data associated with the compromised team. This vulnerability is fixed in 5.9.1.

Weakness: CWE-862

Which versions are affected by CVE-2026-39355?

It affects 1 product.

Products include Kreaweb Genealogy.

How do I fix CVE-2026-39355?

No fix has been published for CVE-2026-39355 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-39355 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39355 exists.

Sources

Also known as GHSA-2rq7-jqm7-w8x4.