CVE-2025-53481 is a high-severity vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) affecting the IPInfo Extension of the Wikimedia Foundation's Mediawiki software. This vulnerability exists in versions 1.39.x prior to 1.39.13, 1.42.x prior to 1.42.7, and 1.43.x prior to 1.43.2. The flaw allows an attacker to cause excessive allocation of resources, leading to potential denial of service (DoS) conditions. Specifically, the IPInfo Extension, which is used to provide geolocation or IP-related information within Mediawiki, does not properly limit or control resource usage when processing certain requests. Since the CVSS vector is AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, the vulnerability can be exploited remotely over the network without any authentication or user interaction, and it impacts availability only, not confidentiality or integrity. The absence of known exploits in the wild suggests it is a recently disclosed issue, but the ease of exploitation and the potential to disrupt service make it a significant threat. Mediawiki is widely used for collaborative documentation, including public wikis and internal knowledge bases, so this vulnerability could be leveraged to disrupt access to critical information repositories.

For European organizations, the impact of this vulnerability can be substantial, especially for those relying on Mediawiki for internal documentation, knowledge management, or public-facing information portals. An attacker exploiting this flaw could cause denial of service by exhausting server resources, leading to downtime or degraded performance. This could disrupt business operations, delay information access, and potentially affect customer-facing services if the wiki is publicly accessible. Given the remote and unauthenticated nature of the exploit, attackers could launch automated attacks at scale, increasing the risk of widespread disruption. Organizations in sectors such as government, education, research institutions, and enterprises that use Mediawiki extensively are particularly at risk. The impact is primarily on availability, which could indirectly affect organizational productivity and reputation.

To mitigate this vulnerability, European organizations should prioritize upgrading the IPInfo Extension to the fixed versions: 1.39.13 or later for the 1.39.x branch, 1.42.7 or later for the 1.42.x branch, and 1.43.2 or later for the 1.43.x branch. If immediate patching is not feasible, organizations should consider temporarily disabling the IPInfo Extension to prevent exploitation. Additionally, implementing rate limiting and resource usage monitoring on Mediawiki servers can help detect and mitigate excessive resource consumption attempts. Network-level protections such as Web Application Firewalls (WAFs) can be configured to detect and block suspicious traffic patterns targeting the IPInfo Extension endpoints. Regularly reviewing Mediawiki logs for unusual spikes in requests or resource usage is also recommended. Finally, organizations should ensure their incident response plans include procedures for handling DoS events related to Mediawiki services.