CVE-2026-43454

/* * PoC for CVE-2026-43454: Linux Kernel netfilter nf_tables Duplicate Device Registration * This PoC demonstrates the logic condition leading to the vulnerability. * Note: Exploiting this requires a vulnerable kernel and specific nftables configuration. */ #include <stdio.h> #include <stdlib.h> #include <string.h> // Simulating kernel structures for demonstration struct nft_hook { char dev_name[16]; struct nft_hook *next; }; struct nft_hook *global_hook_list = NULL; // Simulate nft_netdev_hook_alloc: Adds device to list during hook creation void simulate_hook_alloc(const char *dev_name) { printf("[1] Allocating hook and adding device: %s\n", dev_name); struct nft_hook *new_hook = (struct nft_hook *)malloc(sizeof(struct nft_hook)); strncpy(new_hook->dev_name, dev_name, 15); new_hook->next = global_hook_list; global_hook_list = new_hook; // Device added here initially } // Simulate NETDEV_REGISTER notification handler void simulate_netdev_register_event(const char *dev_name) { printf("[2] Received NETDEV_REGISTER event for: %s\n", dev_name); // VULNERABILITY: Missing check to see if device is already registered // In the vulnerable code, it adds the device again without checking global_hook_list printf("[!] BUG: Logic does not check for existing device. Adding again...\n"); struct nft_hook *dup_hook = (struct nft_hook *)malloc(sizeof(struct nft_hook)); strncpy(dup_hook->dev_name, dev_name, 15); dup_hook->next = global_hook_list; global_hook_list = dup_hook; // Duplicate entry added -> List Corruption } int main() { printf("--- CVE-2026-43454 PoC Simulation ---\n"); // Step 1: Attacker creates a netdev hook (e.g., via nft command) simulate_hook_alloc("eth0"); // Step 2: System triggers a NETDEV_REGISTER event (e.g., interface reset) simulate_netdev_register_event("eth0"); // Step 3: Attempt to traverse (kernel operation) printf("[3] Kernel traversing hook list...\n"); struct nft_hook *curr = global_hook_list; int count = 0; while(curr != NULL) { printf(" - Found hook for: %s\n", curr->dev_name); curr = curr->next; count++; if(count > 5) { printf("[!] Loop detected or list corrupted!\n"); break; } } return 0; }

{"cve": {"id": "CVE-2026-43454", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:16:58.160", "lastModified": "2026-05-11T08:16:14.843", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: Fix for duplicate device in netdev hooks\n\nWhen handling NETDEV_REGISTER notification, duplicate device\nregistration must be avoided since the device may have been added by\nnft_netdev_hook_alloc() already when creating the hook."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "references": [{"url": "https://git.kernel.org/stable/c/2041cdb078041611510fc189410bc70b29f688fb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6d2a95c6890577cc3eab2b20018e16850d7fb094", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b7cdc5a97d02c943f4bdde4d5767ad0c13cad92b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}