x86,fs/resctrl: Prevent out-of-bounds access while offlining CPU when SNC enabled

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64477
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:33 UTC
Updated2026-07-25 10:17:33 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: x86,fs/resctrl: Prevent out-of-bounds access while offlining CPU when SNC enabled The architecture updates the cpu_mask in a domain's header to track which online CPUs are associated with the domain. When this mask becomes empty the architecture initiates offline of the domain that includes calling on resctrl fs to offline the domain. If it is a monitoring domain in which LLC occupancy is tracked resctrl fs forces the limbo handler to clear all busy RMID state associated with the domain. The limbo handler always reads the current event value associated with a busy RMID irrespective of it being checked as part of regular "is it still busy" check or whether it will be forced released anyway. When reading an RMID on a system with SNC enabled the "logical RMID" is converted to the "physical RMID" and this conversion requires the NUMA node ID of the resctrl monitoring domain that is in turn determined by querying the NUMA node ID of any CPU belonging to the monitoring domain. When the monitoring domain is going offline its cpu_mask is empty causing the NUMA node ID query via cpu_to_node() to be done with "nr_cpu_ids" as argument resulting in an out-of-bounds access. Refactor the limbo handler to skip reading the RMID when the RMID will just be forced to no longer be dirty in the domain anyway. Add a safety check to the architecture's RMID reader to protect against this scenario.

Risk And Classification

EPSS: 0.002090000 probability, percentile 0.111770000 (date 2026-07-25)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected e13db55b5a0d447dea63cde772c1078405bbbf96 ebc300b7ee0c669fa76a7a8858298ff32e296103 git Not specified
CNA Linux Linux affected e13db55b5a0d447dea63cde772c1078405bbbf96 be1567992417dc92133e74126de7a6066c825ac9 git Not specified
CNA Linux Linux affected e13db55b5a0d447dea63cde772c1078405bbbf96 58c5ec23b1a238eb75cb0aba6f69d8f9e68ef0b2 git Not specified
CNA Linux Linux affected e13db55b5a0d447dea63cde772c1078405bbbf96 fc16126cc11d9f507130bf84ab137ee0938c900e git Not specified
CNA Linux Linux affected 6.11 Not specified
CNA Linux Linux unaffected 6.11 semver Not specified
CNA Linux Linux unaffected 6.12.96 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.39 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ebc300b7ee0c669fa76a7a8858298ff32e296103 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fc16126cc11d9f507130bf84ab137ee0938c900e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/58c5ec23b1a238eb75cb0aba6f69d8f9e68ef0b2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/be1567992417dc92133e74126de7a6066c825ac9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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