Bug 2481920 (CVE-2026-46084)

Summary: CVE-2026-46084 kernel: RDMA/mana_ib: Disable RX steering on RSS QP destroy
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's RDMA (Remote Direct Memory Access) mana_ib driver. When a Receive Side Scaling Queue Pair (RSS QP) is destroyed, the vPort RX (receive) steering in the firmware is not properly disabled, leaving stale steering configurations. This can lead to receive completions being misdirected to transmit completion queues if network traffic continues and the virtual function (VF) interface is reactivated. The consequence is system instability and a denial of service.
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Description OSIDB Bzimport 2026-05-27 15:02:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

RDMA/mana_ib: Disable RX steering on RSS QP destroy

When an RSS QP is destroyed (e.g. DPDK exit), mana_ib_destroy_qp_rss()
destroys the RX WQ objects but does not disable vPort RX steering in
firmware. This leaves stale steering configuration that still points to
the destroyed RX objects.

If traffic continues to arrive (e.g. peer VM is still transmitting) and
the VF interface is subsequently brought up (mana_open), the firmware
may deliver completions using stale CQ IDs from the old RX objects.
These CQ IDs can be reused by the ethernet driver for new TX CQs,
causing RX completions to land on TX CQs:

  WARNING: mana_poll_tx_cq+0x1b8/0x220 [mana]  (is_sq == false)
  WARNING: mana_gd_process_eq_events+0x209/0x290 (cq_table lookup fails)

Fix this by disabling vPort RX steering before destroying RX WQ objects.
Note that mana_fence_rqs() cannot be used here because the fence
completion is delivered on the CQ, which is polled by user-mode (e.g.
DPDK) and not visible to the kernel driver.

Refactor the disable logic into a shared mana_disable_vport_rx() in
mana_en, exported for use by mana_ib, replacing the duplicate code.
The ethernet driver's mana_dealloc_queues() is also updated to call
this common function.
Comment 1 Keith Grant 2026-05-27 17:19:55 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052701-CVE-2026-46084-b254@gregkh/T