CVE-2026-99138tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)

Official description

In the Linux kernel, the following vulnerability has been resolved: tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO) do_tcp_getsockopt() reads icsk->icsk_ca_ops and dereferences the get_info function pointer without rcu_read_lock(). With BPF struct_ops congestion control, ca_ops can point to dynamically allocated memory that is freed concurrently, resulting in a use-after-free when the kernel dereferences or calls through the stale pointer. BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0 Read of size 8 at addr ffff888013701258 by task exploit/149 do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170 Fix this by wrapping the ca_ops load and get_info call within rcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load the icsk_ca_ops pointer.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/7c312f17917455eedcea29735fa302ebb93cb9b9
• https://git.kernel.org/stable/c/66b831b427301a9c3e485564009d476631413103
• https://git.kernel.org/stable/c/a8b024cbf62b497062c86995737fc303e4cc384e
• https://git.kernel.org/stable/c/8d5fc9e6dc09174d0da6e59678eb8e01a890cbd3
• https://git.kernel.org/stable/c/e057d201640eebb8ed47ec924872c41570a3bd28
• https://git.kernel.org/stable/c/86814e5370068ec2bf0caa6e6d55c3e5bfc6c324
• https://git.kernel.org/stable/c/39aa489e85752f9de214edb0f85e4d578e57af29
• https://git.kernel.org/stable/c/385e474086c2e7e29e2dded690be40dc273e20ee