Critical Remote Code Execution Vulnerability in Redis via Lua Use-After-Free (CVE-2025-49844)

A critical security vulnerability, tracked as CVE-2025-49844, has been identified in Redis, an open-source, in-memory database widely used for caching and data storage. The flaw is rated with a CVSS score of 10.0, indicating maximum severity and potential for significant impact. This vulnerability arises from a use-after-free condition in the Lua scripting engine of Redis, which can be exploited by an authenticated user. By crafting a malicious Lua script, an attacker can manipulate the garbage collector within Redis, triggering the use-after-free bug. Successful exploitation of this flaw allows remote code execution on the affected Redis server, granting attackers the ability to run arbitrary code with the privileges of the Redis process. All Redis versions up to and including 8.2.1 are affected by this vulnerability, as they include the vulnerable Lua scripting functionality. The issue has been addressed in Redis version 8.2.2, which contains the necessary patch to remediate the flaw. As an immediate mitigation for organizations unable to upgrade, Redis administrators are advised to restrict the execution of Lua scripts by disabling the EVAL and EVALSHA commands through Access Control Lists (ACLs). The vulnerability requires authentication, but in environments where Redis is exposed to untrusted users or where credentials are weak, the risk of exploitation is heightened. Security advisories recommend prompt patching and review of user permissions to minimize exposure. The flaw was publicly disclosed in early October 2025, and security researchers have emphasized the critical nature of the bug due to its potential for remote exploitation. No specific products beyond Redis itself have been listed as affected, but any deployment using vulnerable versions is at risk. The vulnerability has been confirmed to be remotely exploitable, making it a high-priority issue for organizations relying on Redis for critical infrastructure. The security community has highlighted the importance of monitoring for suspicious Lua script activity as an additional detection measure. Redis users are urged to consult official advisories and update their systems as soon as possible to prevent compromise. The disclosure underscores the ongoing risks associated with embedded scripting engines in widely deployed software. Organizations should also review their network exposure and ensure Redis instances are not accessible from untrusted networks. The incident serves as a reminder of the importance of timely patch management and the need for defense-in-depth strategies in database deployments.