Bug 2559831 (CVE-2026-99075)

Summary: CVE-2026-99075 kernel: kernel: Denial of Service via memory leak in Rust Binder
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
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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A flaw was found in the Linux kernel's Rust Binder driver. When a thread terminates while holding a pending reference count update for an inter-process communication node, the update is improperly dropped instead of being rescheduled. This desynchronizes internal states and prevents userspace from receiving cleanup notifications, preventing affected nodes from being released. A local user could exploit this flaw to cause a kernel memory leak, resulting in a Denial of Service (DoS) due to resource exhaustion.
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Description OSIDB Bzimport 2026-10-23 13:50:31 UTC 
In the Linux kernel, the following vulnerability has been resolved:

rust_binder: reschedule node refcount update on thread exit

When a thread exits via BINDER_THREAD_EXIT, its pending work items are
cancelled. If a thread exits while holding a pending node refcount
increment (e.g. pushed as deferred work to that thread), the refcount
increment was previously dropped because Node::cancel() and
NodeWrapper::cancel() were no-ops.

Dropping the refcount update leaves the node's delivery state and count
state desynchronized, and userspace will not receive the notification,
which can cause the node to never be freed from the process's nodes tree
when all external references are dropped.

Fix this by implementing DeliverToRead::cancel() for Node and NodeWrapper
to move the pending refcount update to the process's work queue on thread
exit so another thread can deliver it to userspace.