Bug 2536168 (CVE-2026-90309)

Summary: CVE-2026-90309 kernel: RDMA/erdma: Hold CQ references when processing EQ events
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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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A flaw was found in the Linux kernel's RDMA/erdma component. This vulnerability stems from improper management of Completion Queue (CQ) references during Event Queue (EQ) event processing. This can lead to a situation where a CQ is deallocated while still in use by an EQ handler, resulting in memory corruption. Such an issue could cause system instability or a denial of service.
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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 2026-09-17 16:41:08 UTC 
In the Linux kernel, the following vulnerability has been resolved:

RDMA/erdma: Hold CQ references when processing EQ events

EQ handlers look up CQs from dev->cq_xa and invoke CQ completion or
error callbacks outside the xarray lock. erdma_destroy_cq() can erase the
CQ from the xarray and free its queue buffer and doorbell record while a
previously scheduled EQ handler is still using the CQ.

Add a CQ refcount and take a reference under the xarray lock with
refcount_inc_not_zero(). Remove the CQ from the xarray before dropping
the destroy-path reference, then wait for in-flight EQ users before
releasing CQ resources.
Comment 1 gkamathe 2026-09-23 05:11:25 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90309.mbox