CVE-2025-21759: ipv6: mcast: extend RCU protection in igmp6_send()
First published: Thu Feb 27 2025(Updated: )
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. 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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| Linux Kernel | >=2.6.26<6.6.79 | |
| Linux Kernel | >=6.7<6.12.16 | |
| Linux Kernel | >=6.13<6.13.4 | |
| Linux Kernel | =6.14-rc1 | |
| Linux Kernel | =6.14-rc2 |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-21759?
CVE-2025-21759 is classified as a moderate severity vulnerability in the Linux kernel.
How do I fix CVE-2025-21759?
To fix CVE-2025-21759, update your Linux kernel to the latest version that includes the patch for this vulnerability.
What type of vulnerability is CVE-2025-21759?
CVE-2025-21759 is a use-after-free (UAF) vulnerability related to the igmp6_send() function in the Linux kernel.
Who is affected by CVE-2025-21759?
CVE-2025-21759 affects systems running affected versions of the Linux kernel that utilize IPv6 multicast.
What components are involved in CVE-2025-21759?
CVE-2025-21759 involves the RCU (Read-Copy-Update) protection mechanism within the igmp6_send() function.
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