CVE-2026-24042 is a critical security vulnerability classified under CWE-862 (Missing Authorization) affecting Appsmith, an open-source platform used to build admin panels, internal tools, and dashboards. In versions 1.94 and earlier, the application fails to enforce proper authorization on the POST /api/v1/actions/execute API endpoint when handling requests from unauthenticated users. Specifically, if the parameter viewMode is set to false or omitted, the system allows execution of unpublished (edit-mode) actions, which should normally be restricted to authenticated users with editing privileges. This bypasses the intended publish boundary that limits public viewers to executing only published actions. Exploiting this flaw enables attackers to execute arbitrary edit-mode queries and APIs, access sensitive development data, and trigger side effects that could alter system state or data integrity. The vulnerability is remotely exploitable without any authentication or user interaction, increasing its risk profile. Although no patches have been released yet, the high CVSS score of 9.4 reflects the severe confidentiality and integrity impact combined with ease of exploitation. This vulnerability poses a significant threat to organizations relying on Appsmith for internal tooling, as it can lead to unauthorized data disclosure and manipulation.

For European organizations, this vulnerability presents a substantial risk of sensitive data exposure and unauthorized manipulation of internal tools and dashboards built with Appsmith. Since Appsmith is often used to manage critical business processes and internal data, exploitation could lead to leakage of confidential information, disruption of business operations, and potential compliance violations under GDPR due to unauthorized data access. The ability to execute edit-mode actions without authentication means attackers can potentially alter configurations, execute privileged queries, or trigger side effects that impact system availability or data integrity. This could result in operational downtime, reputational damage, and financial losses. Organizations with publicly accessible Appsmith instances are particularly vulnerable, as attackers do not require credentials or user interaction to exploit the flaw. The absence of an official patch increases the urgency for immediate mitigation to prevent exploitation.

Until an official patch is released, European organizations should implement the following specific mitigations: 1) Restrict public access to Appsmith applications by enforcing network-level controls such as VPNs, IP whitelisting, or firewall rules to limit access only to trusted users. 2) Review and harden API gateway or reverse proxy configurations to block or validate requests to the /api/v1/actions/execute endpoint, ensuring that only authenticated and authorized users can invoke edit-mode actions. 3) Implement application-layer authorization checks or custom middleware to enforce strict validation of the viewMode parameter and reject requests attempting to execute unpublished actions from unauthenticated sources. 4) Monitor application logs and network traffic for unusual or unauthorized API calls, especially those omitting or setting viewMode=false, to detect potential exploitation attempts early. 5) Educate development and operations teams about this vulnerability to ensure rapid response and patch deployment once available. 6) Consider isolating or temporarily disabling public-facing Appsmith instances if feasible until a fix is applied.