Bug 2532438 (CVE-2026-89535)

Summary: CVE-2026-89535 kernel: svcrdma: Reorder rpcrdma_rn_unregister before rdma_destroy_id
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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Doc Text:
A flaw was found in the svcrdma module of the Linux kernel. A use-after-free vulnerability can occur due to an incorrect order of operations during the teardown of an RDMA (Remote Direct Memory Access) transport. If a device unregistration process happens concurrently, it can attempt to access a memory region that has already been freed, potentially leading to system instability or 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 2026-09-11 23:07:35 UTC 
In the Linux kernel, the following vulnerability has been resolved:

svcrdma: Reorder rpcrdma_rn_unregister before rdma_destroy_id

svc_rdma_free() caches rdma->sc_cm_id->device before teardown,
then calls rdma_destroy_id(sc_cm_id) which frees the cm_id.
rpcrdma_rn_unregister() follows, but between those two calls
the transport's sc_rn entry is still installed in the device's
rd_xa. A concurrent ib_unregister_device walk can dispatch
svc_rdma_xprt_done() against the now-freed sc_cm_id.

Move rpcrdma_rn_unregister() before rdma_destroy_id() so the
transport's notification entry is removed from the xarray before
the cm_id it references is destroyed.

Also guard the sc_cm_id dereference with a NULL check: the
following patches introduce paths that reach svc_rdma_free()
with sc_cm_id == NULL (listener create failure, ADDR_CHANGE
replacement failure).
Comment 1 gkamathe 2026-09-15 11:05:20 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89535.mbox