Bug 2490006 (CVE-2026-6733)

Summary:	CVE-2026-6733 undici: Undici: Response queue poisoning on reused keep-alive sockets can lead to incorrect response delivery.
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	aazores, abarbaro, alizardo, ataylor, cdrage, cmah, dbruscin, dschmidt, eaguilar, ebaron, erezende, jchui, jhe, jkoehler, jlanda, jolong, kaycoth, kshier, ktsao, kvanderr, lphiri, manissin, nboldt, oaljalju, pjindal, psrna, rhel-process-autobot, rushinde, sdawley, simaishi, smcdonal, stcannon, teagle, watson-tool-maintainers, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in undici. An attacker-controlled upstream server can exploit a vulnerability in Undici's HTTP/1.1 client, specifically related to response queue poisoning on reused keep-alive sockets. This allows the attacker to inject an unsolicited HTTP/1.1 response onto an idle socket. Consequently, when the client dispatches a new request on that socket, it may associate the injected response with the new request, leading to responses being delivered to unintended recipients or requests. This could result in a low impact on data integrity.	Story Points:	---
Clone Of:		Environment:
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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:	2490212, 2490213, 2490214, 2490215
Bug Blocks:

Description OSIDB Bzimport 2026-06-17 19:02:40 UTC

Impact:
Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.

This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.

Patches:
Upgrade to undici v6.26.0, v7.28.0 or v8.5.0.

Workarounds:
Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.