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.

The remote SUSE Linux SLES15 / SLES_SAP15 host has a package installed that is affected by a vulnerability as referenced in the SUSE-SU-2025:1419-1 advisory.

    - CVE-2025-21605: Fixed an output buffer denial of service. (bsc#1241708)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 host has a package installed that is affected by a vulnerability as referenced in the SUSE-SU-2025:1420-1 advisory.

    - CVE-2025-21605: Fixed an output buffer denial of service. (bsc#1241708)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of redis installed on the remote host is prior to 6.2.14-2. It is, therefore, affected by a vulnerability as referenced in the ALAS2REDIS6-2025-012 advisory.

    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. (CVE-2025-21605)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2025-950 advisory.

    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. (CVE-2025-21605)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2025-949 advisory.

    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. (CVE-2025-21605)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the af8d043f-20df-11f0-b9c5-000c295725e4 advisory.

    Axel Mierczuk reports:

                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.


Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
235053	SUSE SLES15 Security Update : redis (SUSE-SU-2025:1419-1)	Nessus	SuSE Local Security Checks	high
235049	SUSE SLES15 Security Update : redis (SUSE-SU-2025:1420-1)	Nessus	SuSE Local Security Checks	high
234981	Amazon Linux 2 : redis (ALASREDIS6-2025-012)	Nessus	Amazon Linux Local Security Checks	high
234947	Amazon Linux 2023 : redis6, redis6-devel (ALAS2023-2025-950)	Nessus	Amazon Linux Local Security Checks	high
234941	Amazon Linux 2023 : valkey, valkey-devel (ALAS2023-2025-949)	Nessus	Amazon Linux Local Security Checks	high
234819	FreeBSD : redis,valkey -- DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client (af8d043f-20df-11f0-b9c5-000c295725e4)	Nessus	FreeBSD Local Security Checks	high

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