CVE-2026-74623 in Linux
Summary
by MITRE • 08/22/2026
In the Linux kernel, the following vulnerability has been resolved:
net: atlantic: free stranded TX buffers on ring deinit
aq_vec_deinit() drains the TX rings with a single aq_ring_tx_clean() call, which frees at most AQ_CFG_TX_CLEAN_BUDGET (256) descriptors and stops at hw_head, which no longer moves once aq_vec_stop() has stopped the hardware and NAPI. Completed descriptors beyond the budget and everything still posted in [hw_head, sw_tail) keep their skb or
xdp_frame when the interface goes down: aq_vec_ring_free() then frees the buffer ring and the references are lost for good.
Today this is a silent memory leak on every interface down under TX/XDP_TX load. With the conversion of the RX path to page_pool posted for net-next it becomes much more visible: XDP_TX frames carry fragment references on the RX ring's page_pool, so a single stranded frame keeps the pool's inflight count above zero forever. page_pool_destroy() then never completes, the pool is leaked together with its pages, and "page_pool_release_retry() stalled pool shutdown" is warned every 60 seconds from that point on, on every ifdown, XDP detach or ring resize under XDP_TX load.
Bring back aq_ring_tx_deinit() as it was before the removal and use it for teardown again, with one extension: TX rings can hold xdp_frames nowadays, so release those too. They are returned with xdp_return_frame() since this runs in process context.
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Analysis
by VulDB Data Team • 08/22/2026
The Linux kernel driver for Atlantic network adapters contains a critical resource management flaw within the transmit ring deinitialization logic that results in persistent memory leaks and potential system instability under specific load conditions. The vulnerability resides in the function responsible for cleaning up transmission rings when an interface is brought down or reset. Specifically, the implementation relies on a single call to clean TX descriptors with a fixed budget limit of two hundred fifty-six entries. This approach fails to account for all pending operations because it stops processing at the hardware head pointer once the stop command has been issued and NAPI polling has ceased. Consequently any descriptors that were completed by the hardware but not yet processed within this limited window remain unhandled, retaining their associated socket buffer or XDP frame references even after the ring structure itself is deallocated.
This oversight leads to a silent memory leak during every instance of interface shutdown when there is active transmit traffic involving either standard network packets or eXpress Data Path transmission operations. The situation becomes significantly more severe with the integration of page pool mechanisms for receive path optimization, as XDP TX frames maintain references to fragments within the RX ring's page pool. When a frame is stranded due to this bug, it prevents the page pool from reaching an idle state because its inflight count remains artificially elevated above zero indefinitely. This blockage causes the destruction of the page pool to hang permanently, resulting in leaked memory pages and triggering repeated kernel warnings regarding stalled pool shutdowns every sixty seconds whenever such a condition is encountered during interface down events or ring resizes under XDP TX load.
From a technical classification perspective this issue aligns with CWE-401 which describes missing release of memory after effective lifetime due to improper cleanup routines, as well as CWE-772 concerning the lack of releasing resources before exit or termination. The operational impact extends beyond simple resource exhaustion; it can lead to progressive degradation of system performance and eventual denial of service through memory pressure if interfaces are frequently cycled under heavy load. Furthermore the persistent warnings generated by the kernel subsystem indicate a deeper synchronization issue where driver state management is out of sync with hardware completion status, potentially masking other underlying stability issues within the network stack.
To mitigate this vulnerability it is necessary to restore and enhance the dedicated deinitialization routine for TX rings that was previously removed from the codebase. This function must iterate through all remaining descriptors in the ring rather than relying on a fixed budget limit, ensuring that every pending operation is properly finalized before the memory structures are freed. Crucially the fix must explicitly handle XDP frames by invoking appropriate return functions such as xdp_return_frame to correctly release fragment references and decrement page pool inflight counts. This ensures that all resources tied to completed but unprocessed descriptors are returned to their respective managers, allowing for clean shutdown sequences without leaving orphaned memory allocations or blocking resource reclamation processes indefinitely.