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Vulnerability · Published Jul 17, 2026 · Assigned by GitHub_M

CVE-2026-55518Avo: Missing Authorization in Avo Association Attach Endpoint Allows Unauthorized Relationship Manipulation and Privilege Escalation

Critical 9.6

In plain English

A critical-severity authorization bypass via user-controlled key in avo from avo-hq. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.6Critical
Exploit odds (30 days)0.4%top 64.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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 & fixed versions

EcosystemPackageFixed inAdvisory
RubyGemsavo3.32.1GHSA-8fq9-273g-6mrg
RubyGemsavo4.0.0.beta.51GHSA-8fq9-273g-6mrg

Affected products (as reported)

VendorProductVersions
avo-hq avo >= 4.0.0.beta.1, < 4.0.0.beta.51< 3.32.1

Weakness: CWE-639, CWE-862, CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

References