Bug 2454805 (CVE-2026-23454)

Summary: CVE-2026-23454 kernel: net: mana: fix use-after-free in mana_hwc_destroy_channel() by reordering teardown
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's mana network driver. A race condition during the destruction of a hardware completion queue (HWC) channel can lead to memory being freed while still in use. This use-after-free vulnerability allows an in-flight interrupt handler to dereference freed memory. This could potentially result in a system crash, leading to a Denial of Service (DoS), or in more severe cases, arbitrary code execution.
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Description OSIDB Bzimport 2026-04-03 16:01:39 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: mana: fix use-after-free in mana_hwc_destroy_channel() by reordering teardown

A potential race condition exists in mana_hwc_destroy_channel() where
hwc->caller_ctx is freed before the HWC's Completion Queue (CQ) and
Event Queue (EQ) are destroyed. This allows an in-flight CQ interrupt
handler to dereference freed memory, leading to a use-after-free or
NULL pointer dereference in mana_hwc_handle_resp().

mana_smc_teardown_hwc() signals the hardware to stop but does not
synchronize against IRQ handlers already executing on other CPUs. The
IRQ synchronization only happens in mana_hwc_destroy_cq() via
mana_gd_destroy_eq() -> mana_gd_deregister_irq(). Since this runs
after kfree(hwc->caller_ctx), a concurrent mana_hwc_rx_event_handler()
can dereference freed caller_ctx (and rxq->msg_buf) in
mana_hwc_handle_resp().

Fix this by reordering teardown to reverse-of-creation order: destroy
the TX/RX work queues and CQ/EQ before freeing hwc->caller_ctx. This
ensures all in-flight interrupt handlers complete before the memory they
access is freed.
Comment 1 Jon Moroney 2026-04-03 19:35:53 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026040317-CVE-2026-23454-a999@gregkh/T