# CVE-2026-74268

## Summary

- **CVE ID:** CVE-2026-74268
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Aug 15, 2026
- **Last Modified:** Sep 14, 2026

## 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.

## Affected Products

- Linux — Linux (d44874910a26f3a8f81edf873a2473363f07f660)
- Linux — Linux (4.16)
- Linux — Linux (0)
- Linux — Linux (6.18.40)
- Linux — Linux (7.1.5)
- Linux — Linux (7.2-rc1)
- Linux — Linux (7.2)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)
- Linux — Linux (6.12.110)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.69%
- **EPSS Percentile:** 51.3

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._