irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64073
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:47 UTC
Updated2026-07-20 15:17:06 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT On PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via run_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0. After irq_work_single() clears BUSY via atomic_cmpxchg(), it still dereferences @work for irq_work_is_hard() and rcuwait_wake_up(). An irq_work_sync() caller on another CPU that enters after BUSY is cleared can observe BUSY==0 immediately, return, and free the work before those accesses complete — causing a use-after-free. Fix this by wrapping run_irq_workd() in guard(rcu)() so that the entire irq_work_single() execution is within an RCU read-side critical section. Then add synchronize_rcu() in irq_work_sync() after rcuwait_wait_event() to ensure the caller waits for the RCU grace period before returning, preventing premature frees.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001860000 probability, percentile 0.083750000 (date 2026-07-20)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 810979682ccc98dbd83f341c18a2e556c30a7164 2dc79362302922cb18f35e262712b5e58de65442 git Not specified
CNA Linux Linux affected 810979682ccc98dbd83f341c18a2e556c30a7164 eef4f71b46a9929ac33e968538c9dd5d96a02460 git Not specified
CNA Linux Linux affected 810979682ccc98dbd83f341c18a2e556c30a7164 684a78183c54c23e70d1cba320f7fc184604210b git Not specified
CNA Linux Linux affected 810979682ccc98dbd83f341c18a2e556c30a7164 18c0456ea2615b1a743a6db739c74411c3b42bc6 git Not specified
CNA Linux Linux affected 810979682ccc98dbd83f341c18a2e556c30a7164 81b582784518196eff1050212a046bc29d3a05dd git Not specified
CNA Linux Linux affected 810979682ccc98dbd83f341c18a2e556c30a7164 91840be8f710370607f949a627e070896faeddb8 git Not specified
CNA Linux Linux affected 5.16 Not specified
CNA Linux Linux unaffected 5.16 semver Not specified
CNA Linux Linux unaffected 6.1.175 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.142 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.92 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.34 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.11 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/18c0456ea2615b1a743a6db739c74411c3b42bc6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2dc79362302922cb18f35e262712b5e58de65442 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/91840be8f710370607f949a627e070896faeddb8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/81b582784518196eff1050212a046bc29d3a05dd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/684a78183c54c23e70d1cba320f7fc184604210b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/eef4f71b46a9929ac33e968538c9dd5d96a02460 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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