CVE-2021-32761

Redis is an in-memory database that persists on disk. A vulnerability involving out-of-bounds read and integer overflow to buffer overflow exists starting with version 2.2 and prior to versions 5.0.13, 6.0.15, and 6.2.5. On 32-bit systems, Redis `*BIT*` command are vulnerable to integer overflow that can potentially be exploited to corrupt the heap, leak arbitrary heap contents or trigger remote code execution. The vulnerability involves changing the default `proto-max-bulk-len` configuration parameter to a very large value and constructing specially crafted commands bit commands. This problem only affects Redis on 32-bit platforms, or compiled as a 32-bit binary. Redis versions 5.0.`3m 6.0.15, and 6.2.5 contain patches for this issue. An additional workaround to mitigate the problem without patching the `redis-server` executable is to prevent users from modifying the `proto-max-bulk-len` configuration parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command.

Summary:

Redis is an in-memory database that persists on disk. A vulnerability involving out-of-bounds read and integer overflow to buffer overflow exists starting with version 2.2 and prior to versions 5.0.13, 6.0.15, and 6.2.5. On 32-bit systems, Redis `*BIT*` command are vulnerable to integer overflow that can potentially be exploited to corrupt the heap, leak arbitrary heap contents or trigger remote code execution. The vulnerability involves changing the default `proto-max-bulk-len` configuration parameter to a very large value and constructing specially crafted commands bit commands. This problem only affects Redis on 32-bit platforms, or compiled as a 32-bit binary. Redis versions 5.0.`3m 6.0.15, and 6.2.5 contain patches for this issue. An additional workaround to mitigate the problem without patching the `redis-server` executable is to prevent users from modifying the `proto-max-bulk-len` configuration parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command.

Reference Links(if available):

  • https://github.com/redis/redis/security/advisories/GHSA-8wxq-j7rp-g8wj
  • https://lists.debian.org/debian-lts-announce/2021/07/msg00017.html
  • CVSS Score (if available)

    v2: / MEDIUMAV:N/AC:M/Au:S/C:P/I:P/A:P

    v3: / HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

    Links to Exploits(if available)