CVE-2023-53463

What it is

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: Do not reset dql stats on NON_FATAL err All ibmvnic resets, make a call to netdev_tx_reset_queue() when re-opening the device. netdev_tx_reset_queue() resets the num_queued and num_completed byte counters. These stats are used in Byte Queue Limit (BQL) algorithms. The difference between these two stats tracks the number of bytes currently sitting on the physical NIC. ibmvnic increases the number of queued bytes though calls to netdev_tx_sent_queue() in the drivers xmit function. When, VIOS reports that it is done transmitting bytes, the ibmvnic device increases the number of completed bytes through calls to netdev_tx_completed_queue(). It is important to note that the driver batches its transmit calls and num_queued is increased every time that an skb is added to the next batch, not necessarily when the batch is sent to VIOS for transmission. Unlike other reset types, a NON FATAL reset will not flush the sub crq tx buffers. Therefore, it is possible for the batched skb array to be partially full. So if there is call to netdev_tx_reset_queue() when re-opening the device, the value of num_queued (0) would not account for the skb's that are currently batched. Eventually, when the batch is sent to VIOS, the call to netdev_tx_completed_queue() would increase num_completed to a value greater than the num_queued. This causes a BUG_ON crash: ibmvnic 30000002: Firmware reports error, cause: adapter problem. Starting recovery... ibmvnic 30000002: tx error 600 ibmvnic 30000002: tx error 600 ibmvnic 30000002: tx error 600 ibmvnic 30000002: tx error 600 ------------[ cut here ]------------ kernel BUG at lib/dynamic_queue_limits.c:27! Oops: Exception in kernel mode, sig: 5 [....] NIP dql_completed+0x28/0x1c0 LR ibmvnic_complete_tx.isra.0+0x23c/0x420 [ibmvnic] Call Trace: ibmvnic_complete_tx.isra.0+0x3f8/0x420 [ibmvnic] (unreliable) ibmvnic_interrupt_tx+0x40/0x70 [ibmvnic] __handle_irq_event_percpu+0x98/0x270 ---[ end trace ]--- Therefore, do not reset the dql stats when performing a NON_FATAL reset.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-10-01 12:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-15 22:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-10-01 12:15 UTC

Last modified

2026-10-15 22:17 UTC

Exploit probability

0.4% · EPSS, next 30 days

Record status

Modified

Affected

• Linux Kernel < 5.15.121
• Linux Kernel < 6.1.39
• Linux Kernel < 6.4.4

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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