Bug 2559672 (CVE-2026-98938)

Summary: CVE-2026-98938 kernel: kernel: Denial of Service via uninitialized memory read in Rust IRQ registration
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's Rust interrupt handling subsystem. During interrupt request (IRQ) registration, an interrupt can be serviced before the registration structure is fully initialized, causing the callback handler to access uninitialized memory. A local attacker could exploit this flaw to cause a Denial of Service (DoS) through a kernel crash or potentially expose sensitive kernel information.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-10-23 12:58:23 UTC
In the Linux kernel, the following vulnerability has been resolved:

rust: irq: pass RegistrationInner as cookie to request_irq

With commit ba268514ea14 ("rust: devres: fix race condition due to
nesting"), Devres::new() returns Result<Self> by value instead of
initializing in-place via PinInit. Because request_irq() is called
inside Devres::new(), registration.inner is still uninitialized when the
IRQ is enabled, so accessing registration.inner.device() in the IRQ
callback can read uninitialized memory.

Fix this by storing the Device and handler pointer in RegistrationInner
and passing RegistrationInner as the IRQ cookie after its fields are
initialized.

This is not needed in mainline because commit 98c63ce4d760 ("rust: irq:
make Registration compatible with lifetime-bound drivers") removed
Devres from irq::Registration and moved request_irq() after all fields
are initialized.