CVE-2026-42205 Avo: Broken Access Control: Unauthorized Execution of Arbitrary Action Classes Across Resources
Authenticated users can execute unauthorized actions on any resource due to broken access control, leading to privilege escalation and data manipulation.
- 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-2026-42205?
CVE-2026-42205 is a high-severity missing authorization vulnerability in avo-hq avo, published on 8 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Avo is a framework to create admin panels for Ruby on Rails apps. Prior to version 3.31.2, a broken access control vulnerability was identified in the ActionsController of the Avo framework. Due to insecure action lookup logic, an authenticated user can execute any Action class (descendants of Avo::BaseAction) on any resource, even if the action is not registered for that specific resource. This leads to Privilege Escalation and unauthorized data manipulation across the entire application. This issue has been patched in version 3.31.2.
Which versions are affected by CVE-2026-42205?
2 open source packages ship an affected version, including avo.
| Package | Affected | Fixed in |
|---|---|---|
avo RubyGems | All versions | 3.31.2 |
avo RubyGems | All versions | 3.31.2 |
How do I fix CVE-2026-42205?
Upgrade avo to 3.31.2 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-42205 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42205 exists.
Sources
Also known as GHSA-qc5p-3mg5-9fh8.