CVE-2025-49844

Redis is an open source, in-memory database that persists on disk. Versions 8.2.1 and below allow an authenticated user to use a specially crafted Lua script to manipulate the garbage collector, trigger a use-after-free and potentially lead to remote code execution. The problem exists in all versions of Redis with Lua scripting. This issue is fixed in version 8.2.2. To workaround this issue without patching the redis-server executable is to prevent users from executing Lua scripts. This can be done using ACL to restrict EVAL and EVALSHA commands.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://github.com/redis/redis/commit/d5728cb5795c966c5b5b1e0f0ac576a7e69af539
• https://github.com/redis/redis/releases/tag/8.2.2
• https://github.com/redis/redis/security/advisories/GHSA-4789-qfc9-5f9q
• http://www.openwall.com/lists/oss-security/2025/10/07/2