GeoServer - Authentication Bypass (CVE-2025-27505)

CVE-2025-27505 is a security vulnerability in GeoServer that allows attackers to bypass REST API security controls by accessing the API index page with certain file extensions, such as .html. This flaw can expose information about installed extensions, potentially aiding reconnaissance and further attacks. The issue is resolved in versions 2.26.3 and 2.25.6.

CrowdSec has been tracking this vulnerability and its exploits since 16th of July 2025.

Data from the CrowdSec community indicates that exploitation of CVE-2025-27505 is highly selective and intelligence-driven. Threat actors use advanced reconnaissance and carefully choose their targets, often as part of sophisticated campaigns or advanced persistent threat operations. CrowdSec data also reveals a clear uptick in attacks involving CVE-2025-27505 over the past week. Activity is above the usual baseline, suggesting growing attention from attackers. This may reflect rising awareness, recent exploit releases, or expanded targeting efforts.

Attackers exploit this vulnerability by directly accessing the /rest.html or /geoserver/rest.html endpoints, exposing sensitive GeoServer configuration information without proper authorization.