VU#943094: ONLYOFFICE ownCloud integration plugin contains a Server-Side Request Forgery (SSRF) vulnerability
ONLYOFFICE's ownCloud integration plugin 9.12 has an SSRF flaw (CVE-2026-84282) letting authenticated admins probe internal networks; no patch exists yet.
CERT/CC published VU#943094 for a server-side request forgery in Ascensio System SIA's ONLYOFFICE ownCloud integration plugin version 9.12, tracked as CVE-2026-84282. The /apps/onlyoffice/ajax/settings/address endpoint does not validate the user-supplied document server URL, so an authenticated administrator can make the ownCloud server send arbitrary requests to localhost and internal hosts. Differences in error responses (connection failures vs SSL/TLS errors) let attackers enumerate open and closed TCP ports for internal reconnaissance. The vendor could not be reached, so no official patch is available; CERT recommends disabling the plugin and applying egress filtering until a fix ships.