unknown

CVE-2026-99250

printk: Postpone kthread startup

Published 3 Nov 2026 · Source updated 3 Nov 2026 · Retrieved 2026-11-04 15:03 UTC · This record may be stale; verify the source

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What happened?

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

printk: Postpone kthread startup

There have been various bug reports related to SMP systems hanging on boot. The reports vary but seem to have some overlap with regard to missed IPI's during SMP setup. The reports also show that reverting NBCON console usage allows the bugs to disappear.

The NBCON kthreads for console printing are started very early during boot using early_initcall(). Since these kthreads are asynchronously enabling/disabling interrupts during early boot, they may be interfering with early SMP setup on some hardware platforms.

Starting the console printing kthreads later has shown to avoid the hanging on systems that could previously reproduce the issue.

Postpone kthread starting until after all arch initcalls have completed.

Description supplied by CVE Program. Formatting is simplified; follow the original advisory for full details.

Affected software and versions

Source-provided software and version information
Software	Version information	Fixed version
LinuxLinux	affected: 76f258bf3f2aae570209319944703a92ac64e29e to < a86bcdd84c8fe7a45f73e12d53fe06fea07d1ceb; affected: 76f258bf3f2aae570209319944703a92ac64e29e to < 7595bacee48bc30b5021eccf199d704d4e5e5374; affected: 76f258bf3f2aae570209319944703a92ac64e29e to < 792acd173da0884f0172c68cb473f42cf93c647e; affected: 76f258bf3f2aae570209319944703a92ac64e29e to < 5f339c46f153184570f16c8e789c9709b14cbe8b	See vendor advisory
LinuxLinux	affected: 6.12; unaffected: 0 to < 6.12; unaffected: 6.12.115 to ≤ 6.12.; unaffected: 6.18.59 to ≤ 6.18.; unaffected: 7.2.13 to ≤ 7.2.; unaffected: 7.3 to ≤	See vendor advisory

Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.

Is it being exploited?

This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.

CISA data retrieved 2026-11-06 16:38 UTC. Check CISA ↗

How to respond

Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.

Sources and remediation references

This public advisory does not determine whether a particular server is affected. Records are refreshed as sources change; verify urgent decisions against the original advisory.

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