CVE-2025-14435 in Mattermost
Summary
by MITRE • 01/16/2026
Mattermost versions 10.11.x <= 10.11.8, 11.1.x <= 11.1.1, 11.0.x <= 11.0.6 fail to prevent infinite re-renders on API errors which allows authenticated users to cause application-level DoS via triggering unbounded component re-render loops.
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Analysis
by VulDB Data Team • 02/27/2026
The vulnerability identified as CVE-2025-14435 affects Mattermost server versions within the 10.11.x, 11.0.x, and 11.1.x release series, specifically impacting versions up to and including 10.11.8, 11.0.6, and 11.1.1. This issue represents a critical application-level denial of service vulnerability that stems from improper error handling within the application's rendering logic. The flaw manifests when authenticated users trigger API errors that cause the application to enter infinite re-render loops, effectively consuming excessive system resources and rendering the service unavailable to legitimate users.
The technical root cause of this vulnerability lies in the application's failure to implement proper bounds checking and error recovery mechanisms during component rendering operations. When API calls fail or return error responses, the Mattermost application does not adequately terminate or limit the re-rendering process that occurs in response to these errors. This creates a scenario where the rendering engine continuously attempts to reprocess the same error state, leading to an unbounded loop that consumes CPU cycles and memory resources without termination. The vulnerability specifically impacts the client-side rendering components that handle API responses, where error states are not properly managed to prevent recursive rendering operations.
From an operational perspective, this vulnerability presents a significant risk to Mattermost deployments as it allows authenticated users to initiate denial of service conditions with relatively simple actions. The attack requires only legitimate authentication credentials to the Mattermost instance, making it particularly dangerous in environments where user access controls may be insufficient or where compromised accounts exist. The infinite re-render loops can cause the application to become unresponsive, leading to service degradation or complete outage for all users, including administrators who may need to access the system to respond to the attack. This vulnerability directly impacts the availability and reliability of communication platforms that organizations depend upon for critical operations.
The impact of this vulnerability aligns with CWE-835, which addresses infinite loops in software applications, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should implement immediate mitigations including applying the latest security patches released by Mattermost, implementing rate limiting on API endpoints to prevent excessive re-rendering attempts, and establishing monitoring systems to detect unusual resource consumption patterns. Additionally, administrators should consider implementing network-level controls to limit API access from suspicious sources and ensure that proper access controls are in place to minimize the potential impact of compromised accounts. The vulnerability demonstrates the importance of robust error handling and resource management in web applications, particularly in collaborative platforms where user-generated content processing can create complex rendering scenarios that require careful resource management to prevent abuse.