CVE-2026-55518
Avo - Missing Authorization in Avo Association Attach Endpoint Allows Unauthorized Relationship Manipulation and Privilege Escalation
Severity by source
Trivy's own label is CRITICAL. Rated critical by GHSA, Ruby Advisory DB.
Description
Avo is a framework to create admin panels for Ruby on Rails apps. Prior to 3.32.1 and 4.0.0.beta.51, Avo's association attach workflow checks attach_<association>? in the UI and GET /resources/:resource/:id/:related/new path, but the actual write endpoint, POST /resources/:resource/:id/:related, does not run the same authorization check before mutating the association through Avo::AssociationsController#create. An authenticated low-privileged Avo user can bypass hidden or disabled attach controls and directly attach related records to a parent record by sending a crafted POST request, which can lead to privilege escalation and cross-tenant data exposure where associations represent authorization-bearing relationships. This issue is fixed in versions 3.32.1 and 4.0.0.beta.51.
Affected packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| rubygems::GitHub Security Advisory RubyGems | avo | 3.32.1, 4.0.0.beta.51 |
| rubygems::Ruby Advisory Database | avo | >= 3.32.1, < 4.0.0.beta.1, >= 4.0.0.beta.51 |
References
- https://advisories.gitlab.com/gem/avo/CVE-2026-55518
- https://github.com/advisories/GHSA-8fq9-273g-6mrg
- https://github.com/avo-hq/avo
- https://github.com/avo-hq/avo/commit/995928e586fd1788dd496bd51c4dbe4a79cb2b9c
- https://github.com/avo-hq/avo/pull/4568
- https://github.com/avo-hq/avo/releases/tag/v3.32.1
- https://github.com/avo-hq/avo/security/advisories/GHSA-8fq9-273g-6mrg
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/avo/CVE-2026-55518.yml