# CVE-2022-50409: linux: In the Linux kernel, the following vulnerability has been resolved:  net: If sock is dead don't access sock's sk_wq i...

CVE-2022-50409 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-50409, released September 18, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-50409
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 18, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  net: If sock is dead don't access sock's sk_wq in sk_stream_wait_memory  Fixes the below NULL pointer dereference:    [...]   [   14.471200] Call Trace:   [   14.471562]  <TASK>   [   14.471882]  lock_acquire+0x245/0x2e0   [   14.472416]  ? remove_wait_queue+0x12/0x50   [   14.473014]  ? _raw_spin_lock_irqsave+0x17/0x50   [   14.473681]  _raw_spin_lock_irqsave+0x3d/0x50   [   14.474318]  ? remove_wait_queue+0x12/0x50   [   14.474907]  remove_wait_queue+0x12/0x50   [   14.475480]  sk_stream_wait_memory+0x20d/0x340   [   14.476127]  ? do_wait_intr_irq+0x80/0x80   [   14.476704]  do_tcp_sendpages+0x287/0x600   [   14.477283]  tcp_bpf_push+0xab/0x260   [   14.477817]  tcp_bpf_sendmsg_redir+0x297/0x500   [   14.478461]  ? __local_bh_enable_ip+0x77/0xe0   [   14.479096]  tcp_bpf_send_verdict+0x105/0x470   [   14.479729]  tcp_bpf_sendmsg+0x318/0x4f0   [   14.480311]  sock_sendmsg+0x2d/0x40   [   14.480822]  ____sys_sendmsg+0x1b4/0x1c0   [   14.481390]  ? copy_msghdr_from_user+0x62/0x80   [   14.482048]  ___sys_sendmsg+0x78/0xb0   [   14.482580]  ? vmf_insert_pfn_prot+0x91/0x150   [   14.483215]  ? __do_fault+0x2a/0x1a0   [   14.483738]  ? do_fault+0x15e/0x5d0   [   14.484246]  ? __handle_mm_fault+0x56b/0x1040   [   14.484874]  ? lock_is_held_type+0xdf/0x130   [   14.485474]  ? find_held_lock+0x2d/0x90   [   14.486046]  ? __sys_sendmsg+0x41/0x70   [   14.486587]  __sys_sendmsg+0x41/0x70   [   14.487105]  ? intel_pmu_drain_pebs_core+0x350/0x350   [   14.487822]  do_syscall_64+0x34/0x80   [   14.488345]  entry_SYSCALL_64_after_hwframe+0x63/0xcd   [...]  The test scenario has the following flow:  thread1                               thread2 -----------                           ---------------  tcp_bpf_sendmsg   tcp_bpf_send_verdict    tcp_bpf_sendmsg_redir              sock_close     tcp_bpf_push_locked                 __sock_release      tcp_bpf_push                         //inet_release       do_tcp_sendpages                    sock->ops->release        sk_stream_wait_memory          	   // tcp_close           sk_wait_event                      sk->sk_prot->close            release_sock(__sk);             ***                                                 lock_sock(sk);                                                   __tcp_close                                                     sock_orphan(sk)                                                       sk->sk_wq  = NULL                                                 release_sock             ****            lock_sock(__sk);           remove_wait_queue(sk_sleep(sk), &wait);              sk_sleep(sk)              //NULL pointer dereference              &rcu_dereference_raw(sk->sk_wq)->wait  While waiting for memory in thread1, the socket is released with its wait queue because thread2 has closed it. This caused by tcp_bpf_send_verdict didn't increase the f_count of psock->sk_redir->sk_socket->file in thread1.  We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory before accessing the wait queue.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.0.3-1 | [DEBIAN-CVE-2022-50409](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50409.md) | Sep 18, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.0.3-1 | [DEBIAN-CVE-2022-50409](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50409.md) | Sep 18, 2025 |
| Linux | linux Debian 14 | 6.0.3-1 | [DEBIAN-CVE-2022-50409](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50409.md) | Sep 18, 2025 |

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