CVE-2021-32761: Debian Linux

High severity, CVSS 7.5. EPSS: 31.2% chance of exploitation in the next 30 days.

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.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only; version 11.0 only
• Fedoraproject Fedora: version 33 only; version 34 only
• Redislabs Redis: from 2.2.0, before 5.0.13 (fixed in 5.0.13); from 6.0, before 6.0.15 (fixed in 6.0.15); from 6.2.0, before 6.2.5 (fixed in 6.2.5)

Published 2021-07-21. Last modified 2026-06-17.