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CVE-2026-64459: Linux

9.8

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се по мрежата, без особени условия, без вход и без действие от потребителя.

    Описание

    Оригинално описание

    In the Linux kernel, the following vulnerability has been resolved: tcp: restore RCU grace period in tcp_ao_destroy_sock Commit 51e547e8c89c ("tcp: Free TCP-AO/TCP-MD5 info/keys without RCU") removed the call_rcu() callback from tcp_ao_destroy_sock(), arguing that "the destruction of info/keys is delayed until the socket destructor" and therefore "no one can discover it anymore". That argument does not hold for the call site in tcp_connect() (net/ipv4/tcp_output.c:4327-4332). At that point the socket is in TCP_SYN_SENT, has already been inserted into the inet ehash by inet_hash_connect() in tcp_v4_connect(), and is therefore very much discoverable: any softirq running tcp_v4_rcv() on another CPU can take the socket out of the ehash, walk into tcp_inbound_hash(), and load tp->ao_info via implicit RCU before bh_lock_sock_nested() is taken on the destroying CPU. The reader path then enters __tcp_ao_do_lookup() (net/ipv4/tcp_ao.c:208) which re-loads tp->ao_info via rcu_dereference_check(); the re-load can still observe the (about-to-be-freed) pointer because there is no synchronize_rcu() between rcu_assign_pointer(tp->ao_info, NULL) and tcp_ao_info_free() in tcp_ao_destroy_sock(). The captured pointer is then walked at line 223: hlist_for_each_entry_rcu(key, &ao->head, node, ...) The writer's synchronous kfree() is free to complete between the line 218 re-fetch and the line 223 hlist iteration. The slab is reused (or simply LIST_POISON1-stamped if not yet reused) and the iteration walks attacker-controlled or poison memory in softirq context. Reproducer (no debug shim, stock x86_64 v7.1-rc2 SMP+KASAN, QEMU+KVM): an unprivileged uid=1000 process inside CLONE_NEWUSER|CLONE_NEWNET installs TCP_MD5SIG + TCP_AO_ADD_KEY on a TCP socket, sprays forged TCP-AO segments toward its eventual 4-tuple via raw sockets, then calls connect(). The md5-wins reconciliation in tcp_connect() fires tcp_ao_destroy_sock(); the softirq backlog reader on the loopback NAPI path crashes on

    Засегнати продукти

    • Linux Linux: 51e547e8c89c661f6fbede4a28b1d33b13625683 преди 657646c08c94ef7b9dbe468fe7828032216f9841; 51e547e8c89c661f6fbede4a28b1d33b13625683 преди 4caf12c778fed3dc3824cf36263be5e2c491fbd0; 51e547e8c89c661f6fbede4a28b1d33b13625683 преди 8bc4d43bccbd60efe85d0a44d5bf41762f2f0c30
    • Linux Linux: 6.18; преди 6.18; 6.18.39 до 6.18.*; 7.1.4 до 7.1.*; от 7.2 нататък

    История

    • 25 юли 2026 Публикувано

    Други уязвимости в Linux Linux

    Първоизточници

    CVE-2026-64459: Linux | freedomonline.bg