Bug 2348509 (CVE-2025-21760)

Summary:	CVE-2025-21760 kernel: ndisc: extend RCU protection in ndisc_send_skb()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	dfreiber, drow, jburrell, rhel-process-autobot, vkumar, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the Linux kernel. The `ndisc_send_skb()` function, responsible for handling Neighbor Discovery (ND) messages in IPv6, can be called without proper Read-Copy-Update (RCU) protection. This missing protection can lead to a Use-After-Free (UAF) vulnerability. A Use-After-Free vulnerability occurs when a program attempts to use memory after it has been freed, which can lead to system instability or potentially arbitrary code execution.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-02-27 03:01:13 UTC

In the Linux kernel, the following vulnerability has been resolved:

ndisc: extend RCU protection in ndisc_send_skb()

ndisc_send_skb() can be called without RTNL or RCU held.

Acquire rcu_read_lock() earlier, so that we can use dev_net_rcu()
and avoid a potential UAF.

Comment 1 Michal Findra 2025-02-27 11:44:33 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022604-CVE-2025-21760-fb9d@gregkh/T