CVE-2026-99250: Linux kernel · printk: Postpone kthread startup
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 5 Nov 2026, 00:01 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or none- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 3 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 4 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther 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
Upgrade to a Linux kernel version that includes the fix postponing the startup of console printing kthreads until after all architecture initialization calls have completed. This change prevents the boot hang issue on SMP systems. No additional mitigation steps are indicated.
Description
A Linux kernel vulnerability involving early startup of console printing kernel threads (kthreads) can cause system hangs on SMP systems during boot. The issue arises because these kthreads start very early and asynchronously enable/disable interrupts, potentially interfering with SMP setup. The fix delays the startup of these kthreads until after all architecture-specific initialization calls complete, preventing the hang.
References
- ubuntu.com/security/CVE-2026-99250 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99250 (opens in a new tab)
- git.kernel.org/stable/c/a86bcdd84c8fe7a45f73e12d53fe06fea07d1ceb (opens in a new tab)
- git.kernel.org/stable/c/792acd173da0884f0172c68cb473f42cf93c647e (opens in a new tab)
- git.kernel.org/stable/c/7595bacee48bc30b5021eccf199d704d4e5e5374 (opens in a new tab)
- git.kernel.org/stable/c/5f339c46f153184570f16c8e789c9709b14cbe8b (opens in a new tab)