CVE-2026-89549
Received
Received - Intake
Linux Kernel SunRPC Thread Pool Routing Flaw
Vulnerability report for CVE-2026-89549, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-11
Last updated on: 2026-09-11
Assigner: kernel.org
Description
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().
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
