CVE-2026-89549: Linux kernel · sunrpc: route to a populated pool in svc_pool_for_cpu()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that updates svc_pool_for_cpu() to skip pools without threads and route work to populated pools, preventing indefinite connection hangs. Users should apply the official Linux kernel patches that address this issue. Since this is a kernel-level fix, upgrading to patched kernel versions is the recommended remediation.
Description
A vulnerability in the Linux kernel's sunrpc subsystem was resolved that could cause connection hangs. The issue occurs when svc_set_num_threads() distributes threads unevenly across service pools, leaving some pools without threads. Transports routed to these threadless pools are enqueued but never serviced, causing indefinite hangs. The fix ensures svc_pool_for_cpu() skips pools without threads and falls back to the next populated pool, trading NUMA locality for guaranteed servicing.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89549 (opens in a new tab)
- git.kernel.org/stable/c/011479cf9a7657d4a3e7cc42a784ac63df594170 (opens in a new tab)
- git.kernel.org/stable/c/8f766d2d0b4dabf54f8b35812df2b4f481d13316 (opens in a new tab)
- git.kernel.org/stable/c/9d04d64ad192439835ed9884d767353061c3ed6f (opens in a new tab)
- git.kernel.org/stable/c/f6310491c4cdb88af73aa551ec9df1f10a90c709 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89549 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89549 (opens in a new tab)
- git.kernel.org/linus/f6310491c4cdb88af73aa551ec9df1f10a90c709 (opens in a new tab)