net: ioam6: fix OOB and missing lock_CVE-2026-43083

9.1 / 10

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Description

In the Linux kernel, the following vulnerability has been resolved:

net: ioam6: fix OOB and missing lock

When trace->type.bit6 is set:

if (trace->type.bit6) {
...
queue = skb_get_tx_queue(dev, skb);
qdisc = rcu_dereference(queue->qdisc);

This code can lead to an out-of-bounds access of the dev->_tx[] array
when is_input is true. In such a case, the packet is on the RX path and
skb->queue_mapping contains the RX queue index of the ingress device. If
the ingress device has more RX queues than the egress device (dev) has
TX queues, skb_get_queue_mapping(skb) will exceed dev->num_tx_queues.
Add a check to avoid this situation since skb_get_tx_queue() does not
clamp the index. This issue has also revealed that per queue visibility
cannot be accurate and will be replaced later as a new feature.

While at it, add missing lock around qdisc_qstats_qlen_backlog(). The
function __ioam6_fill_trace_data() is called from both softirq and
process contexts, hence the use of spin_lock_bh() here.

AI Analysis

Out-of-bounds access vulnerability in the Linux kernel's ioam6 module

Basic Information

ID CVE-2026-43083

Source Linux

Published May 6, 2026 at 07:40

Modified May 8, 2026 at 12:40

Affected Product

Vendor Linux

Product Linux

Version b63c5478e9cb1d1504eb02d9dac827ad24612b32

Affected Versions Linux Linux b63c5478e9cb1d1504eb02d9dac827ad24612b32
Linux Linux b63c5478e9cb1d1504eb02d9dac827ad24612b32
Linux Linux b63c5478e9cb1d1504eb02d9dac827ad24612b32
Linux Linux 5.17

AI Assessment

AI Score 9.1 / 10

AI Severity Critical

Vendor Linux Foundation

Product Linux Kernel

Version b63c5478e9cb1d1504eb02d9dac827ad24612b32, 5.17

References

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    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ioam6: fix OOB and missing lock\n\nWhen trace->type.bit6 is set:\n\n    if (trace->type.bit6) {\n        ...\n        queue = skb_get_tx_queue(dev, skb);\n        qdisc = rcu_dereference(queue->qdisc);\n\nThis code can lead to an out-of-bounds access of the dev->_tx[] array\nwhen is_input is true. In such a case, the packet is on the RX path and\nskb->queue_mapping contains the RX queue index of the ingress device. If\nthe ingress device has more RX queues than the egress device (dev) has\nTX queues, skb_get_queue_mapping(skb) will exceed dev->num_tx_queues.\nAdd a check to avoid this situation since skb_get_tx_queue() does not\nclamp the index. This issue has also revealed that per queue visibility\ncannot be accurate and will be replaced later as a new feature.\n\nWhile at it, add missing lock around qdisc_qstats_qlen_backlog(). The\nfunction __ioam6_fill_trace_data() is called from both softirq and\nprocess contexts, hence the use of spin_lock_bh() here.",
    "published": "2026-05-06T07:40:18.504Z",
    "modified": "2026-05-08T12:40:26.791Z",
    "type": "cve",
    "title": "net: ioam6: fix OOB and missing lock",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/6d1d9ed9b409e0662241e3d245d574a18f643494\nhttps://git.kernel.org/stable/c/95a1334748c95dd15546056280ade0c4b8dd7b78\nhttps://git.kernel.org/stable/c/b30b1675aa2bcf0491fd3830b051df4e08a7c8ca",
    "id": "CVE-2026-43083",
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