CVE-2021-32675
redis: Denial of service via Redis Standard Protocol (RESP) request
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · October 4, 2021
Updated · August 4, 2026
Description
A flaw was found in redis. 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). This flaw allows an unauthenticated, remote user delivering specially crafted requests over multiple connections to cause the server to allocate a significant amount of memory, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-770 · Allocation of Resources Without Limits or Throttling