CVE-2025-53371 in DiscordNotifications
Summary
by MITRE • 07/10/2025
DiscordNotifications is an extension for MediaWiki that sends notifications of actions in your Wiki to a Discord channel. DiscordNotifications allows sending requests via curl and file_get_contents to arbitrary URLs set via $wgDiscordIncomingWebhookUrl and $wgDiscordAdditionalIncomingWebhookUrls. This allows for DOS by causing the server to read large files. SSRF is also possible if there are internal unprotected APIs that can be accessed using HTTP POST requests, which could also possibly lead to RCE. This vulnerability is fixed in commit 1f20d850cbcce5b15951c7c6127b87b927a5415e.
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Analysis
by VulDB Data Team • 07/10/2025
The vulnerability identified as CVE-2025-53371 affects the DiscordNotifications extension for MediaWiki, a widely used wiki software platform that powers numerous collaborative websites and documentation systems. This extension enables administrators to route wiki activity notifications to Discord channels, facilitating real-time communication between wiki editors and community members. The flaw resides in how the extension handles webhook URLs, specifically through the configuration parameters $wgDiscordIncomingWebhookUrl and $wgDiscordAdditionalIncomingWebhookUrls that control where notifications are sent. When configured incorrectly or exploited, these parameters create a dangerous attack surface that can be leveraged by malicious actors to compromise the underlying MediaWiki server infrastructure.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the DiscordNotifications extension. The extension directly utilizes the user-provided webhook URLs in HTTP requests through both curl and file_get_contents functions, which are standard PHP methods for making web requests. This design pattern creates a path for arbitrary code execution and resource exhaustion attacks when attackers can manipulate the URL parameters to point to malicious or resource-heavy endpoints. The vulnerability manifests as a combination of denial of service and server-side request forgery issues, where the server itself becomes an unwitting proxy for malicious requests. The lack of proper URL validation means that attackers can specify URLs that point to internal network resources or files that cause excessive resource consumption when retrieved.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable complete system compromise. The denial of service aspect allows attackers to cause the MediaWiki server to consume excessive bandwidth and memory resources by directing it to download large files or repeatedly access resource-intensive endpoints. This can effectively shut down wiki services and impact thousands of users who depend on the platform for collaboration and information sharing. The server-side request forgery component presents a more severe threat, as it can enable attackers to access internal APIs and services that are typically protected from external access. When combined with internal network vulnerabilities or exposed administrative interfaces, this SSRF capability can potentially lead to remote code execution, allowing attackers to gain full control over the server and access sensitive wiki content or user data. The vulnerability affects organizations that rely on MediaWiki for critical documentation, knowledge bases, and collaborative platforms, making it particularly dangerous for enterprises and educational institutions.
Mitigation strategies for this vulnerability require immediate action from system administrators to update their MediaWiki installations to versions containing the fix referenced in commit 1f20d850cbcce5b15951c7c6127b87b927a5415e. Organizations should also implement network-level restrictions to prevent outbound requests to internal resources from their MediaWiki servers, particularly when using the DiscordNotifications extension. The recommended approach includes validating and sanitizing all webhook URL inputs, implementing proper access controls to restrict which users can configure webhook URLs, and monitoring for unusual outbound network activity that might indicate exploitation attempts. Security teams should also consider implementing web application firewalls and network segmentation to limit the potential impact of successful attacks. This vulnerability aligns with CWE-918, which addresses server-side request forgery, and relates to ATT&CK techniques involving command and control communications and privilege escalation through server-side vulnerabilities. The fix in the referenced commit likely includes input validation mechanisms and proper URL sanitization to prevent the extension from making unauthorized requests to arbitrary endpoints, thereby eliminating both the denial of service and server-side request forgery attack vectors.