CVE-2026-23278

/* * PoC for CVE-2026-23278 * This code demonstrates the logic to trigger the nf_tables catchall element bug. * It requires a Linux kernel with the vulnerability and libmnl. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> int main() { printf("[+] Attempting to trigger CVE-2026-23278\n"); // 1. Create a Netlink socket to communicate with the kernel int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); if (fd < 0) { perror("socket"); return -1; } // 2. Construct a batched transaction (NFQNL_MSG_BATCH) // - Create a table // - Create a set with catchall elements // - Add a new catchall element in the transaction // - Delete the set holding the catchall elements in the same transaction // - Abort the transaction // Note: Detailed Netlink attribute construction omitted for brevity. // The key is the sequence of operations causing the abort path to miss elements. printf("[+] Sending malformed transaction...\n"); // send_malicious_batch(fd); close(fd); printf("[+] Check dmesg for WARNING: nft_data_release\n"); return 0; }

{"cve": {"id": "CVE-2026-23278", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-03-20T09:16:13.690", "lastModified": "2026-04-02T09:16:20.537", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: always walk all pending catchall elements\n\nDuring transaction processing we might have more than one catchall element:\n1 live catchall element and 1 pending element that is coming as part of the\nnew batch.\n\nIf the map holding the catchall elements is also going away, its\nrequired to toggle all catchall elements and not just the first viable\ncandidate.\n\nOtherwise, we get:\n WARNING: ./include/net/netfilter/nf_tables.h:1281 at nft_data_release+0xb7/0xe0 [nf_tables], CPU#2: nft/1404\n RIP: 0010:nft_data_release+0xb7/0xe0 [nf_tables]\n [..]\n __nft_set_elem_destroy+0x106/0x380 [nf_tables]\n nf_tables_abort_release+0x348/0x8d0 [nf_tables]\n nf_tables_abort+0xcf2/0x3ac0 [nf_tables]\n nfnetlink_rcv_batch+0x9c9/0x20e0 [..]"}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnetfilter: nf_tables: siempre recorrer todos los elementos catchall pendientes\n\nDurante el procesamiento de transacciones podríamos tener más de un elemento catchall:\n1 elemento catchall activo y 1 elemento pendiente que viene como parte del nuevo lote.\n\nSi el mapa que contiene los elementos catchall también va a desaparecer, es necesario alternar todos los elementos catchall y no solo el primer candidato viable.\n\nDe lo contrario, obtenemos:\n ADVERTENCIA: ./include/net/netfilter/nf_tables.h:1281 en nft_data_release+0xb7/0xe0 [nf_tables], CPU#2: nft/1404\n RIP: 0010:nft_data_release+0xb7/0xe0 [nf_tables]\n [..]\n __nft_set_elem_destroy+0x106/0x380 [nf_tables]\n nf_tables_abort_release+0x348/0x8d0 [nf_tables]\n nf_tables_abort+0xcf2/0x3ac0 [nf_tables]\n nfnetlink_rcv_batch+0x9c9/0x20e0 [..]"}], "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/77c26b5056d693ffe5e9f040e946251cdb55ae55", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7cb9a23d7ae40a702577d3d8bacb7026f04ac2a9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/de47a88c6b807910f05703fb6605f7efdaa11417", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/eb0948fa13298212c5f8b30ee48efdae4389ab09", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}