CVE-2026-72915 Mastodon: Personally-identifying information disclosure due to incorrect access control validation
Logged-in users can access other users' email and IP addresses due to incorrect access control in the admin collections controller.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72915?
CVE-2026-72915 is a high-severity vulnerability in mastodon, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Mastodon is a free, open-source social network server based on ActivityPub. From 4.6.0-beta.1 until 4.6.4 and 4.7.0-beta.1, any logged-in local user could use the show action in app/controllers/admin/collections_controller.rb to access personally identifying information about another local user in a collection because the controller used the general collection policy instead of the admin collection policy namespace. The exposed data included the other user's current email address and last-used IP address. This issue is fixed in versions 4.6.4 and 4.7.0-beta.1.
Weakness: CWE-200
Which versions are affected by CVE-2026-72915?
1 open source package ship an affected version, including mastodon.
| Package | Affected | Fixed in |
|---|---|---|
mastodon Bitnami | From 4.6.0 | 4.6.4 |
How do I fix CVE-2026-72915?
Upgrade mastodon to 4.6.4 or later.
Is CVE-2026-72915 being exploited?
There is no known exploitation of CVE-2026-72915 in the wild and no public exploit code.
Sources
Also known as BIT-mastodon-2026-72915, GHSA-hx34-2pfw-2qfj.