# CVE-2021-32761: redis: Redis is an in-memory database that persists on disk

CVE-2021-32761 is fixed in 4 products on 1 platform, first by redis 5:4.0.9-1ubuntu0.2+esm3, released October 4, 2021. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-32761
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.3010
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 21, 2021

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | redis Ubuntu 18.04.6 LTS (bionic) | 5:4.0.9-1ubuntu0.2+esm3 | [redis 5:4.0.9-1ubuntu0.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-redis-5-4.0.9-1ubuntu0.2-esm3.md) | Oct 4, 2021 |
| Linux | redis-sentinel Ubuntu 18.04.6 LTS (bionic) | 5:4.0.9-1ubuntu0.2+esm3 | [redis-sentinel 5:4.0.9-1ubuntu0.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-redis-sentinel-5-4.0.9-1ubuntu0.2-esm3.md) | Oct 4, 2021 |
| Linux | redis-server Ubuntu 18.04.6 LTS (bionic) | 5:4.0.9-1ubuntu0.2+esm3 | [redis-server 5:4.0.9-1ubuntu0.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-redis-server-5-4.0.9-1ubuntu0.2-esm3.md) | Oct 4, 2021 |
| Linux | redis-tools Ubuntu 18.04.6 LTS (bionic) | 5:4.0.9-1ubuntu0.2+esm3 | [redis-tools 5:4.0.9-1ubuntu0.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-redis-tools-5-4.0.9-1ubuntu0.2-esm3.md) | Oct 4, 2021 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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