Bug 2361883 (CVE-2025-21605)

Summary:	CVE-2025-21605 redis: Redis DoS Vulnerability due to unlimited growth of output buffers abused by unauthenticated client
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	abarbaro, anpicker, aprice, bbrownin, bdettelb, caswilli, cdaley, doconnor, dranck, hasun, jchui, jdobes, jeder, jfula, jhe, jmitchel, jowilson, jsamir, jtanner, jvasik, jwong, kaycoth, kgaikwad, kholdawa, kshier, ktsao, lcouzens, mskarbek, nboldt, nyancey, oezr, ometelka, orabin, psegedy, psrna, ptisnovs, rblanco, syedriko, teagle, ttakamiy, vmugicag, xdharmai, xiaoxwan, zzhou
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Redis server. This flaw allows an unauthenticated client to cause an 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 runs out of memory.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2361977
Bug Blocks:

Description OSIDB Bzimport 2025-04-23 16:02:09 UTC

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.

Comment 4 errata-xmlrpc 2025-05-05 01:36:49 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.4 Telecommunications Update Service

Via RHSA-2025:4441 https://access.redhat.com/errata/RHSA-2025:4441

Comment 5 errata-xmlrpc 2025-05-06 15:30:22 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.6 Telecommunications Update Service

Via RHSA-2025:4561 https://access.redhat.com/errata/RHSA-2025:4561

Comment 6 errata-xmlrpc 2025-05-06 17:22:34 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:4577 https://access.redhat.com/errata/RHSA-2025:4577

Comment 7 errata-xmlrpc 2025-05-07 02:33:23 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Extended Update Support

Via RHSA-2025:4607 https://access.redhat.com/errata/RHSA-2025:4607

Comment 8 errata-xmlrpc 2025-05-12 01:28:14 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Extended Update Support

Via RHSA-2025:4789 https://access.redhat.com/errata/RHSA-2025:4789

Comment 9 errata-xmlrpc 2025-05-12 01:29:27 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2025:4788 https://access.redhat.com/errata/RHSA-2025:4788

Comment 10 errata-xmlrpc 2025-05-13 11:56:43 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:7429 https://access.redhat.com/errata/RHSA-2025:7429

Comment 11 errata-xmlrpc 2025-05-13 11:58:19 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:7438 https://access.redhat.com/errata/RHSA-2025:7438

Comment 12 errata-xmlrpc 2025-05-13 16:02:02 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2025:7509 https://access.redhat.com/errata/RHSA-2025:7509

Comment 13 errata-xmlrpc 2025-05-14 01:42:04 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2025:7538 https://access.redhat.com/errata/RHSA-2025:7538

Comment 14 errata-xmlrpc 2025-05-15 15:43:07 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:7686 https://access.redhat.com/errata/RHSA-2025:7686