CVE-2021-32675: Debian Linux

High severity, CVSS 7.5. EPSS: 16.1% chance of exploitation in the next 30 days.

Redis is an open source, in-memory database that persists on disk. When parsing an incoming Redis Standard Protocol (RESP) request, Redis allocates memory according to user-specified values which determine the number of elements (in the multi-bulk header) and size of each element (in the bulk header). An attacker delivering specially crafted requests over multiple connections can cause the server to allocate significant amount of memory. Because the same parsing mechanism is used to handle authentication requests, this vulnerability can also be exploited by unauthenticated users. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate this problem without patching the redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This can be done in different ways: Using network access control tools like firewalls, iptables, security groups, etc. or Enabling TLS and requiring users to authenticate using client side certificates.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only
• Fedoraproject Fedora: version 33 only; version 34 only; version 35 only
• Netapp Management Services For Element Software: affected versions not specified
• Netapp Management Services For Netapp Hci: affected versions not specified
• Oracle Communications Operations Monitor: version 4.3 only; version 4.4 only; version 5.0 only
• Redis Redis: from 5.0.0, before 5.0.14 (fixed in 5.0.14); from 6.0.0, before 6.0.16 (fixed in 6.0.16); from 6.2.0, before 6.2.6 (fixed in 6.2.6)

Published 2021-10-04. Last modified 2026-06-17.