CVE-2025-21605

7.5 HIGH
Published: April 23, 2025 Modified: November 14, 2025

Description

Redis is an open source, in-memory database that persists on disk. In versions starting at 2.6 and prior to 7.4.3, An unauthenticated client can cause unlimited growth of output buffers, until the server runs out of memory or is killed. By default, the Redis configuration does not limit the output buffer of normal clients (see client-output-buffer-limit). Therefore, the output buffer can grow unlimitedly over time. As a result, the service is exhausted and the memory is unavailable. When password authentication is enabled on the Redis server, but no password is provided, the client can still cause the output buffer to grow from "NOAUTH" responses until the system will run out of memory. This issue has been patched in version 7.4.3. 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. Either using network access control tools like firewalls, iptables, security groups, etc, or enabling TLS and requiring users to authenticate using client side certificates.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/redis/redis/releases/tag/7.4.3
Source: security-advisories@github.com
Release Notes
https://github.com/redis/redis/security/advisories/GHSA-r67f-p999-2gff
Source: security-advisories@github.com
Third Party Advisory
https://github.com/valkey-io/valkey/releases/tag/8.1.1
Source: af854a3a-2127-422b-91ae-364da2661108
Release Notes
https://lists.debian.org/debian-lts-announce/2025/05/msg00014.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.1%
32th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

redis debian lfprojects