Bug 2536412 (CVE-2026-90113)

Summary: CVE-2026-90113 kernel: netdevsim: update queue NAPI association on queue reset
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 netdevsim component of the Linux kernel. When a network queue is reset, the system fails to correctly update the association with its NAPI (New API) structure. This can allow a local attacker, by performing a queue reset and then initiating a queue dump via Netlink, to trigger a use-after-free read. This vulnerability could lead to system instability and 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 17:45:04 UTC 
In the Linux kernel, the following vulnerability has been resolved:

netdevsim: update queue NAPI association on queue reset

In netdevsim, receive queues (struct nsim_rq) embed their own struct
napi_struct. When queue reset is performed (e.g. via queue_reset
debugfs), nsim_queue_start() swaps in a newly allocated struct nsim_rq,
and nsim_queue_mem_free() later deletes and frees the old one.

However, nsim_queue_start() failed to update the queue-to-NAPI mapping
via netif_queue_set_napi(). As a result, dev->_rx[idx].napi continued to
point to the old NAPI struct. After the old queue was freed, a subsequent
queue dump via Netlink (NETDEV_CMD_QUEUE_GET) triggered a KASAN
slab-use-after-free read in nla_put_napi_id() when accessing
rxq->napi->napi_id.

Fix this by calling netif_queue_set_napi() in nsim_queue_start() to
associate the new NAPI with the RX queue, and clear the association
with netif_queue_set_napi(..., NULL) in nsim_del_napi() during teardown.
Comment 1 Keith Grant 2026-09-23 12:24:15 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90113.mbox