Bug 2414466 (CVE-2025-40149)

Summary: CVE-2025-40149 kernel: tls: Use __sk_dst_get() and dst_dev_rcu() in get_netdev_for_sock()
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: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel’s TLS implementation (net/tls/tls_device.c). The function get_netdev_for_sock() is invoked during setsockopt(), which is not executed under RCU (Read-Copy-Update) protection. It previously used sk_dst_get(sk)->dev, which can lead to a use-after-free (UAF) if the sk’s destination is freed
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Description OSIDB Bzimport 2025-11-12 11:01:30 UTC 
In the Linux kernel, the following vulnerability has been resolved:

tls: Use __sk_dst_get() and dst_dev_rcu() in get_netdev_for_sock().

get_netdev_for_sock() is called during setsockopt(),
so not under RCU.

Using sk_dst_get(sk)->dev could trigger UAF.

Let's use __sk_dst_get() and dst_dev_rcu().

Note that the only ->ndo_sk_get_lower_dev() user is
bond_sk_get_lower_dev(), which uses RCU.
Comment 1 Alexander B 2025-11-13 16:57:58 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025111257-CVE-2025-40149-2c48@gregkh/T