# CVE-2026-89549

## Summary

- **CVE ID:** CVE-2026-89549
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:

sunrpc: route to a populated pool in svc_pool_for_cpu()

svc_set_num_threads() spreads the requested threads evenly across the
service's pools (base = nrservs / sv_nrpools).  When a service runs
fewer threads than it has pools -- e.g. an nfsd configured with fewer
threads than the host has NUMA nodes while running in "pernode" or
"percpu" mode -- the trailing pools are left with no threads at all.

svc_xprt_enqueue() selects a pool from the CPU servicing the transport,
queues the transport on that pool's sp_xprts, and only wakes a thread
from the same pool.  Each thread services exclusively its own pool, so a
transport that lands on a threadless pool is enqueued on sp_xprts and
never picked up: the connection hangs indefinitely.

Have svc_pool_for_cpu() skip pools that currently have no threads,
falling back to the next populated pool.  This trades NUMA locality for
a guarantee that the work is actually serviced.  sp_nrthreads is only
updated under the service mutex; the lockless read here is a best-effort
routing hint, so annotate it with data_race().

## Affected Products

- Linux — Linux (bfd241600a3b0db4fe43c859f1460d0a958d924a)
- Linux — Linux (2.6.19)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/011479cf9a7657d4a3e7cc42a784ac63df594170)
- [CNA](https://git.kernel.org/stable/c/9d04d64ad192439835ed9884d767353061c3ed6f)
- [CNA](https://git.kernel.org/stable/c/8f766d2d0b4dabf54f8b35812df2b4f481d13316)
- [CNA](https://git.kernel.org/stable/c/f6310491c4cdb88af73aa551ec9df1f10a90c709)
- [CNA](https://git.kernel.org/stable/c/9accc25e5af0bac8479f6054e674b2c593c45281)
- [CNA](https://git.kernel.org/stable/c/6f66d38e2a6c78d48723ea17ad86135ec80ca24b)
- [CNA](https://git.kernel.org/stable/c/d79d7b9e8acbb53e2d60f6b24afc13e2f15e691f)
- [CNA](https://git.kernel.org/stable/c/edb20e8c03aebacb409968c99d046f509c6c485a)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.72%
- **EPSS Percentile:** 52.1

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