CVE-2026-42205: Avo Framework Privilege Escalation in Ruby on Rails Admin Panels
The National Vulnerability Database has detailed CVE-2026-42205, a high-severity broken access control vulnerability in the Avo framework, used for creating admin panels in Ruby on Rails applications. Prior to version 3.31.2, the ActionsController within Avo contained insecure action lookup logic.
This flaw allows any authenticated user to execute any Avo::BaseAction descendant on any resource, even if that action is explicitly not registered for the specific resource. This isn’t just a minor bug; it’s a direct path to privilege escalation and unauthorized data manipulation across the entire application. The attacker’s calculus here is straightforward: gain initial access, then exploit this to elevate privileges and move laterally, potentially exfiltrating or corrupting sensitive data.
The National Vulnerability Database confirms the issue has been patched in Avo version 3.31.2. The CVSSv3.1 score is 8.8 (High), reflecting the network attack vector, low attack complexity, low privileges required, and complete compromise of confidentiality, integrity, and availability.
What This Means For You
- If your organization uses Avo for Ruby on Rails admin panels, you need to immediately verify your Avo framework version. This isn't a theoretical risk; it's a critical access control bypass. Update to version 3.31.2 or later without delay. Then, audit your application logs for any unusual action executions by authenticated users in your Avo admin interfaces.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-42205: Avo Framework Unauthorized Action Execution - Free Tier
title: CVE-2026-42205: Avo Framework Unauthorized Action Execution - Free Tier
id: scw-2026-05-08-ai-1
status: experimental
level: high
description: |
Detects attempts to access Avo actions directly via the '/avo/actions/' path with an 'action=' parameter in the query string, indicative of the broken access control vulnerability in Avo Framework versions prior to 3.31.2. This rule targets the core exploit mechanism allowing authenticated users to execute arbitrary Avo actions, leading to privilege escalation.
author: SCW Feed Engine (AI-generated)
date: 2026-05-08
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42205/
tags:
- attack.persistence
- attack.t1505.003
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/avo/actions/'
cs-uri-query|contains:
- 'action='
sc-status:
- 200
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42205 | Privilege Escalation | Avo framework < 3.31.2 |
| CVE-2026-42205 | Auth Bypass | Avo framework ActionsController |
| CVE-2026-42205 | Broken Access Control | Avo framework insecure action lookup logic |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 09, 2026 at 01:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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