The Spring Framework's spring-websocket module generates WebSocket session IDs that are insufficiently random, making them potentially predictable. This vulnerability (CVE-2026-41838) affects multiple versions of Spring Framework, specifically 5.3.0 to 5.3.48, 6.1.0 to 6.1.27, 6.2.0 to 6.2.18, and 7.0.0 to 7.0.7. Exploitation may be possible when combined with weak authorization rules, potentially allowing an attacker to guess session IDs and hijack WebSocket sessions. No official patch or remediation guidance is currently provided by the vendor, and no known exploits are reported in the wild.

Successful exploitation could lead to unauthorized access to WebSocket sessions due to predictable session IDs, resulting in confidentiality breaches. The vulnerability does not impact integrity or availability directly. The CVSS vector indicates the attack requires network access, high attack complexity, low privileges, and user interaction, with high confidentiality impact but no integrity or availability impact.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, review and strengthen authorization rules around WebSocket sessions to mitigate risk. Avoid relying solely on session ID unpredictability for security.