CVE-2026-43083

/* * PoC Concept for CVE-2026-43083 * This script attempts to trigger the OOB access by sending packets * with IOAM6 trace type bit6 set, targeting an interface setup * where RX queues > TX queues. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <net/sock.h> // Conceptual kernel module structure to trigger the condition // Actual exploitation requires specific network topology configuration void trigger_vuln(struct sk_buff *skb) { // Manipulate skb to simulate the condition: // 1. Ensure IOAM6 trace data is present with bit6 set // 2. Ensure is_input path is taken // 3. Set skb->queue_mapping to a high value (>= dev->num_tx_queues) // If the device has fewer TX queues than the RX queue index mapped here, // the kernel will panic or crash in __ioam6_fill_trace_data. printk(KERN_INFO "Attempting to trigger CVE-2026-43083\n"); } // Note: Full PoC would require crafting specific IOAM6 packets via raw sockets // and configuring the network interfaces with asymmetric queue counts.

{"cve": {"id": "CVE-2026-43083", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:21.493", "lastModified": "2026-05-08T13:16:38.550", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "references": [{"url": "https://git.kernel.org/stable/c/6d1d9ed9b409e0662241e3d245d574a18f643494", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/95a1334748c95dd15546056280ade0c4b8dd7b78", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b30b1675aa2bcf0491fd3830b051df4e08a7c8ca", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}