---
cve: "CVE-2026-43083"
severity: "CRITICAL"
cvss: 9.1
epss: "44%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-05-06 10:16:21"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-17T20:49:06+02:00"
---

# CVE-2026-43083

> 9.1 CRITICAL

## Beschreibung

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.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 6.18.24
- Kernel ≥ 6.19.14

## Referenzen

- <https://git.kernel.org/stable/c/6d1d9ed9b409e0662241e3d245d574a18f643494>
- <https://git.kernel.org/stable/c/95a1334748c95dd15546056280ade0c4b8dd7b78>
- <https://git.kernel.org/stable/c/b30b1675aa2bcf0491fd3830b051df4e08a7c8ca>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-43083) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_