CVE-2025-21605
published 2025-04-23CVE-2025-21605: 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…
PriorityP345high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.85%
54.5th percentile
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.
Affected
21 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | redict | < redict 7.3.5+ds-1 (forky) | redict 7.3.5+ds-1 (forky) |
| debian | redis | < redict 7.3.5+ds-1 (forky) | redict 7.3.5+ds-1 (forky) |
| debian | valkey | < redict 7.3.5+ds-1 (forky) | redict 7.3.5+ds-1 (forky) |
| lfprojects | valkey | >= 0 < 8.1.1+dfsg1-1 | 8.1.1+dfsg1-1 |
| lfprojects | valkey | >= 0 < 8.1.1+dfsg1-1 | 8.1.1+dfsg1-1 |
| lfprojects | valkey | >= 7.2.4 < 7.2.9 | 7.2.9 |
| lfprojects | valkey | >= 8.0.0 < 8.0.3 | 8.0.3 |
| lfprojects | valkey | >= 8.1.0 < 8.1.1 | 8.1.1 |
| msrc | azl3_valkey_8.0.2-1_on_azure_linux_3.0 | — | — |
| msrc | azl3_valkey_8.0.3-1_on_azure_linux_3.0 | — | — |
| msrc | cbl2_redis_6.2.18-3_on_cbl_mariner_2.0 | — | — |
| msrc | cbl2_redis_6.2.20-1_on_cbl_mariner_2.0 | — | — |
| redis | redis | — | — |
| redis | redis | >= 0 < 5:6.0.16-1+deb11u6 | 5:6.0.16-1+deb11u6 |
| redis | redis | >= 0 < 5:7.0.15-1~deb12u4 | 5:7.0.15-1~deb12u4 |
| redis | redis | >= 0 < 5:7.0.15-3.1 | 5:7.0.15-3.1 |
| redis | redis | >= 0 < 5:7.0.15-3.1 | 5:7.0.15-3.1 |
| redis | redis | >= 2.6.0 < 6.2.18 | 6.2.18 |
| redis | redis | >= 7.0 < 7.2.8 | 7.2.8 |
| redis | redis | >= 7.4.0 < 7.4.3 | 7.4.3 |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
osv7.5HIGH
vendor_debian7.5HIGH
vendor_msrc7.5HIGH
vendor_redhat7.5HIGH
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Red Hat
redis: Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client
vendor_redhat·2025-04-23·CVSS 7.5
CVE-2025-21605 [HIGH] CWE-770 redis: Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client
redis: Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client
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 memor
Microsoft
Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client
vendor_msrc·2025-04-08·CVSS 7.5
CVE-2025-21605 [HIGH] CWE-770 Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client
Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
GitHub_M: GitHub_M
Customer Action Required: Yes
Remediatio
Debian
CVE-2025-21605: redict - Redis is an open source, in-memory database that persists on disk. In versions s...
vendor_debian·2025·CVSS 7.5
CVE-2025-21605 [HIGH] CVE-2025-21605: redict - Redis is an open source, in-memory database that persists on disk. In versions s...
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
OSV
CVE-2025-21605: Redis is an open source, in-memory database that persists on disk
osv·2025-04-23·CVSS 7.5
CVE-2025-21605 [HIGH] CVE-2025-21605: Redis is an open source, in-memory database that persists on disk
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
No detection rules found.
No public exploits indexed.
https://github.com/redis/redis/releases/tag/7.4.3https://github.com/redis/redis/security/advisories/GHSA-r67f-p999-2gffhttps://github.com/valkey-io/valkey/releases/tag/8.1.1https://lists.debian.org/debian-lts-announce/2025/05/msg00014.htmlhttps://www.vicarius.io/vsociety/posts/cve-2025-21605-detection-script-memory-exhaustion-vulnerability-in-redis-databasehttps://www.vicarius.io/vsociety/posts/cve-2025-21605-mitigation-script-memory-exhaustion-vulnerability-in-redis-database
2025-04-23
Published