CVE-2026-71415 Kirby: File upload permissions are not checked during processing of chunk data
Authenticated users can bypass upload authorization checks to fill temporary storage, causing denial of service for other users.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-71415?
CVE-2026-71415 is a high-severity missing authorization vulnerability in getkirby kirby, published on 31 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Kirby is an open-source content management system. From 5.0.0 until 5.5.2, Kirby's REST API chunk upload handler in src/Api/Upload.php did not run the relevant upload authorization preflight in Kirby\Api\Upload::process() before Kirby\Api\Upload::processChunk() persisted chunk data. An authenticated user with the access.panel permission enabled but with files.create, files.replace, and user/users.update permissions disabled could submit requests with an Upload-Length header and leave unfinished chunks in site/cache/.uploads for 24 hours. Repeating this process could consume attacker-controlled temporary storage, prevent other users from uploading files, or prevent site logic from storing data, although final permission checks still prevented unauthorized files from reaching the content or site/accounts directories. This issue is fixed in version 5.5.2.
Weakness: CWE-862
Which versions are affected by CVE-2026-71415?
2 open source packages ship an affected version, including getkirby/cms.
| Package | Affected | Fixed in |
|---|---|---|
getkirby/cms Packagist | From 5.0.0 | 5.5.2 |
getkirby/cms Packagist | From 5.0.0 | 5.5.2 |
How do I fix CVE-2026-71415?
Upgrade getkirby/cms to 5.5.2 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-71415 being exploited?
There is no known exploitation of CVE-2026-71415 in the wild and no public exploit code.
Sources
Also known as GHSA-67mx-6wf2-92xp.