CVE-2026-43083 net: ioam6: fix OOB and missing lock
An out-of-bounds access in the Linux kernel IOAM6 module allows attackers to cause denial of service or potentially execute code via crafted network packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43083?
CVE-2026-43083 is a critical memory corruption vulnerability in Linux kernel, published on 6 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-125
Which versions are affected by CVE-2026-43083?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43083?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-43083 being exploited?
There is no known exploitation of CVE-2026-43083 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-85929, BELL-CVE-2026-43083, DEBIAN-CVE-2026-43083, GHSA-29pf-hv9p-f96v, ROOT-OS-DEBIAN-12-CVE-2026-43083, ROOT-OS-DEBIAN-13-CVE-2026-43083 and 2 more.