CVE-2021-29478: 
Redis vulnerability analysis and mitigation

Redis, an open-source in-memory data structure store, was found to contain an integer overflow vulnerability (CVE-2021-29478) in version 6.2 before 6.2.3. The vulnerability was discovered in May 2021 and affects Redis when used as a database, cache, and message broker. The issue specifically impacts Redis 6.2 versions prior to 6.2.3, while Redis 6.0 and earlier versions are not directly affected by this vulnerability (GitHub Advisory, NVD).

The vulnerability is an integer overflow bug that could be exploited through the COPY command when working with large intsets. The exploitation involves changing the default set-max-intset-entries configuration value, creating a large set key consisting of integer values, and using the COPY command to duplicate it. The vulnerability has been assigned a CVSS v3.1 base score of 7.5 (High) with the vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (GitHub Advisory).

If successfully exploited, this vulnerability could lead to heap corruption and potentially result in remote code execution. While the integer overflow bug exists in all versions of Redis starting with 2.6, it could only be exploited through the COPY command in version 6.2, where it could result in corrupted RDB or DUMP payload (GitHub Advisory, Fedora Update).

The vulnerability requires network access and low privileges but high attack complexity to exploit. An attacker would need to be able to modify the set-max-intset-entries configuration parameter and have the ability to create and manipulate large set keys (GitHub Advisory).

The primary mitigation is to upgrade to Redis version 6.2.3 which contains the fix for this vulnerability. For users unable to immediately upgrade, a workaround is available by preventing users from modifying the set-max-intset-entries configuration parameter. This can be accomplished by using ACL to restrict unprivileged users from using the CONFIG SET command (GitHub Advisory, Gentoo Security).