Bug 2461544 (CVE-2026-31644) - CVE-2026-31644 kernel: net: lan966x: fix use-after-free and leak in lan966x_fdma_reload()
Summary: CVE-2026-31644 kernel: net: lan966x: fix use-after-free and leak in lan966x_f...
Keywords:
Status: NEW
Alias: CVE-2026-31644
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-24 15:07 UTC by OSIDB Bzimport
Modified: 2026-04-24 21:36 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-04-24 15:07:39 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: lan966x: fix use-after-free and leak in lan966x_fdma_reload()

When lan966x_fdma_reload() fails to allocate new RX buffers, the restore
path restarts DMA using old descriptors whose pages were already freed
via lan966x_fdma_rx_free_pages(). Since page_pool_put_full_page() can
release pages back to the buddy allocator, the hardware may DMA into
memory now owned by other kernel subsystems.

Additionally, on the restore path, the newly created page pool (if
allocation partially succeeded) is overwritten without being destroyed,
leaking it.

Fix both issues by deferring the release of old pages until after the
new allocation succeeds. Save the old page array before the allocation
so old pages can be freed on the success path. On the failure path, the
old descriptors, pages and page pool are all still valid, making the
restore safe. Also ensure the restore path re-enables NAPI and wakes
the netdev, matching the success path.


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