sunrpc: route to a populated pool in svc_pool_for_cpu()
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 7 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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().
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.19 and later | 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.19 and later Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89549
- 2026-10-03 Alias added: GHSA-j6w6-qx29-46gg
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-18 Priority changed: LOW → MEDIUM
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/9accc25e5af0bac8479f6054e674b2c593c45281
- https://git.kernel.org/stable/c/6f66d38e2a6c78d48723ea17ad86135ec80ca24b
- https://git.kernel.org/stable/c/d79d7b9e8acbb53e2d60f6b24afc13e2f15e691f
- https://git.kernel.org/stable/c/edb20e8c03aebacb409968c99d046f509c6c485a
- https://git.kernel.org/stable/c/011479cf9a7657d4a3e7cc42a784ac63df594170
- https://git.kernel.org/stable/c/9d04d64ad192439835ed9884d767353061c3ed6f
- https://git.kernel.org/stable/c/8f766d2d0b4dabf54f8b35812df2b4f481d13316
- https://git.kernel.org/stable/c/f6310491c4cdb88af73aa551ec9df1f10a90c709
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Sources
- CVE-2026-89549 · CVE Program
- CVE-2026-89549 · NVD
- FIRST EPSS
- GHSA-j6w6-qx29-46gg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89549 · Red Hat security data · CC BY 4.0
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