CVE-2026-86285 BookStack Attachment Edit Endpoint AttachmentController.php getUpdateForm access control
Attackers can bypass access controls to modify attachments via the edit endpoint, requiring a patch for BookStack.
- 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-2026-86285?
CVE-2026-86285 is a medium-severity missing authorization vulnerability in BookStack, published on 7 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability was detected in BookStack up to 26.05.2. Affected by this issue is the function AttachmentController::getUpdateForm of the file app/Uploads/Controllers/AttachmentController.php of the component Attachment Edit Endpoint. The manipulation of the argument ID results in improper access controls. The attack may be launched remotely. The exploit is now public and may be used. The patch is identified as 4e406c41c4c8060a5795e74c66fb96362e54f400. It is advisable to implement a patch to correct this issue.
Which versions are affected by CVE-2026-86285?
How do I fix CVE-2026-86285?
No fix has been published for CVE-2026-86285 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-2026-86285 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86285 exists.
Sources
Also known as GHSA-9rg8-hwc3-hh5g.