CVE-2026-68527 Missing authorization in Concrete CMS
Attackers with limited calendar permissions can read, modify, or delete events on unauthorized calendars due to improper authorization checks in the edit dialog.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-68527?
CVE-2026-68527 is a medium-severity missing authorization vulnerability in Concrete CMS, published on 10 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
Concrete CMS versions 8.3.0 through 9.5.2 are vulnerable to an authorization bypass in the Calendar event edit dialog (concrete/controllers/dialog/event/edit.php). The dialog checked permissions against the calendar identifier supplied in the request rather than the calendar owning the targeted event occurrence. A user with the "Add Event" permission on a single calendar could read and overwrite events on calendars they were not permitted to access, and could delete an event's original local occurrence. Publishing the injected version to the live calendar, which demotes the previously approved version, additionally required the actor's approve_calendar_event workflow rights or an auto-approving workflow. The Concrete CMS Security Team gave this a rank of 5.9 with CVSS 4.0 vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.
Weakness: CWE-639
Which versions are affected by CVE-2026-68527?
How do I fix CVE-2026-68527?
No fix has been published for CVE-2026-68527 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-2026-68527 being exploited?
There is no known exploitation of CVE-2026-68527 in the wild and no public exploit code.
Sources
Also known as GHSA-xgrc-pc59-m8cp.