CVE-2026-42205 is a high-severity security vulnerability in avo (rubygems), affecting versions < 3.31.2. It is fixed in 3.31.2.
Summary A critical Broken Access Control vulnerability was identified in the ActionsController of the Avo framework (v3.x). 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. Details The vulnerability exists in the actionclass method within app/controllers/avo/actionscontroller.rb. Vulnerable Code The controller identifies the action class to execute solely based on the params[:actionid] by searching through all BaseAction descendants. It fails to verify whether the requested action is actually permitted or registered for the resource context specified in the request URL (e.g., /admin/resources/posts/actions). Consequently, an attacker can invoke sensitive actions (e.g., Avo::Actions::ToggleAdmin) through an unrelated resource endpoint (e.g., Post), bypassing the intended resource-action mapping. Impact This flaw results in significant security risks: Privilege Escalation: An authenticated user with low privileges can execute administrative actions (like toggling admin roles) to escalate their own or others' permissions. Unauthorized Operations: Actions designed for restricted resources can be triggered against any record ID in the database. Data Integrity Compromise: Attackers can perform unauthorized destructive operations (e.g., Delete, Archive, or Update) on records they should not have access to. Proof of Concept (PoC) Steps to Reproduce: Log in to the Avo admin panel with limited permissions. Identify a target record ID (e.g., User ID: 1) and a sensitive action class (e.g., Avo::Actions::ToggleAdmin). Send a POST request to a resource endpoint where the target action is not registered: URL: POST /admin/resources/posts/actions Payload: actionid=Avo::Actions::ToggleAdmin&fields[avoresourceids]=1 The server executes the ToggleAdmin logic on User 1, even though the request was made through the posts resource context. PoC Script Snippet: Remediation Restrict the action lookup to only those actions explicitly registered for the current resource context: Discoverer Illunight
CVE-2026-42205 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (3.31.2). Upgrading removes the vulnerable code path.
rubygems
avo (< 3.31.2)avo → 3.31.2 (rubygems)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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CVE-2026-42205 is a high-severity security vulnerability in avo (rubygems), affecting versions < 3.31.2. It is fixed in 3.31.2.
CVE-2026-42205 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
avo (rubygems) versions < 3.31.2 is affected.
Yes. CVE-2026-42205 is fixed in 3.31.2. Upgrade to this version or later.
Whether CVE-2026-42205 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade avo to 3.31.2 or later.