Cyber Resilience

CVE-2026-42205

High

Published: 08 May 2026

Published
08 May 2026
Modified
12 May 2026
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0029 21.2th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-42205 is a high-severity Improper Access Control (CWE-284) vulnerability. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 21.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability details

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…

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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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Broken access control directly enables authenticated users to bypass authorization checks and execute arbitrary registered actions, resulting in privilege escalation.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-27591Shared CWE-284, CWE-639
CVE-2026-20628Shared CWE-284
CVE-2026-41906Shared CWE-639
CVE-2025-48619Shared CWE-284
CVE-2025-21405Shared CWE-284
CVE-2026-24303Shared CWE-284
CVE-2026-24290Shared CWE-284
CVE-2026-38807Shared CWE-639
CVE-2026-41086Shared CWE-284
CVE-2026-48904Shared CWE-284

Affected Assets

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-284 CWE-639

Ensuring access control decisions are made and applied to every request before enforcement directly prevents improper access control by requiring policy-based checks.

addresses: CWE-284 CWE-639

Enforcing approved authorizations directly implements access control policies to block unauthorized access.

addresses: CWE-284

The access control policy and procedures directly mandate and enforce proper access control mechanisms across the organization.

addresses: CWE-284

Device lock enforces restricted access until re-authentication, directly reducing unauthorized use of active sessions.

addresses: CWE-284

Supervision and review of access control activities directly detects and remediates improper access configurations or usages.

addresses: CWE-284

Explicitly identifying and documenting actions permitted without identification or authentication enforces proper access control boundaries by defining justified exceptions.

addresses: CWE-284

By automatically labeling outputs with security attributes, the control supports attribute-based enforcement and reduces exploitability of improper access control weaknesses.

addresses: CWE-284

Associating and retaining security attributes with data directly supports enforcement of access control decisions across storage, processing, and transmission.

References