Bug 2348531 (CVE-2025-21758)

Summary: CVE-2025-21758 kernel: ipv6: mcast: add RCU protection to mld_newpack()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, mijjapur, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-02-27 03:02:15 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ipv6: mcast: add RCU protection to mld_newpack()

mld_newpack() can be called without RTNL or RCU being held.

Note that we no longer can use sock_alloc_send_skb() because
ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep.

Instead use alloc_skb() and charge the net->ipv6.igmp_sk
socket under RCU protection.
Comment 1 Michal Findra 2025-02-27 15:44:20 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022604-CVE-2025-21758-9f8c@gregkh/T