CVE-2026-56843 Missing authorization in Plesk
Low-privileged users can bypass authorization to view other tenants' cleartext FTP credentials, enabling cross-tenant code execution.
- 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-2026-56843?
CVE-2026-56843 is a critical missing authorization vulnerability in Webpros Plesk, published on 8 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Incorrect authorization in the XML-RPC API of WebPros Plesk before 18.0.78.4 allows a low-privileged authenticated customer to look up domains they do not own, because ownership is enforced only for certain lookup filters and schema validation is bypassed for legacy protocol versions. This results in cross-tenant disclosure of other tenants' FTP credentials stored in cleartext, which can be leveraged to execute code as another tenant's system user.
Weakness: CWE-522
Which versions are affected by CVE-2026-56843?
How do I fix CVE-2026-56843?
No fix has been published for CVE-2026-56843 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-2026-56843 being exploited?
There is no known exploitation of CVE-2026-56843 in the wild and no public exploit code.
Sources
Also known as GHSA-m4rp-7vj2-ggpc.