CVE-2025-40347

Deferred Deferred - Pending Action

BaseFortify

Publication date: 2025-12-16

Last updated on: 2026-06-01

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net: enetc: fix the deadlock of enetc_mdio_lock After applying the workaround for err050089, the LS1028A platform experiences RCU stalls on RT kernel. This issue is caused by the recursive acquisition of the read lock enetc_mdio_lock. Here list some of the call stacks identified under the enetc_poll path that may lead to a deadlock: enetc_poll -> enetc_lock_mdio -> enetc_clean_rx_ring OR napi_complete_done -> napi_gro_receive -> enetc_start_xmit -> enetc_lock_mdio -> enetc_map_tx_buffs -> enetc_unlock_mdio -> enetc_unlock_mdio After enetc_poll acquires the read lock, a higher-priority writer attempts to acquire the lock, causing preemption. The writer detects that a read lock is already held and is scheduled out. However, readers under enetc_poll cannot acquire the read lock again because a writer is already waiting, leading to a thread hang. Currently, the deadlock is avoided by adjusting enetc_lock_mdio to prevent recursive lock acquisition.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-12-16

Last Modified

2026-06-01

Generated

2026-07-06

AI Q&A

2025-12-16

EPSS Evaluated

2026-07-05

NVD

CVE-2025-40347

EUVD

EUVD-2025-203640

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability is a deadlock issue in the Linux kernel's enetc network driver. It occurs due to recursive acquisition of a read lock called enetc_mdio_lock. Specifically, when the enetc_poll function acquires the read lock, a higher-priority writer tries to acquire the same lock and causes preemption. The writer waits because the read lock is held, but the readers cannot reacquire the lock because the writer is waiting, leading to a deadlock and thread hang. The issue was fixed by changing enetc_lock_mdio to prevent recursive lock acquisition.

Mitigation Strategies

Apply the fix that adjusts enetc_lock_mdio to prevent recursive lock acquisition, which avoids the deadlock. This involves updating the Linux kernel to a version where this issue is resolved.

Impact Analysis

This vulnerability can cause the affected system to hang or become unresponsive due to a deadlock in the network driver. This can lead to degraded network performance or complete loss of network connectivity on systems using the LS1028A platform with the affected Linux kernel, potentially impacting system stability and availability.

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