CVE-2026-31407

/* * Conceptual PoC for CVE-2026-31407 * Triggering out-of-bounds read in netfilter conntrack */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> #define NETLINK_NETFILTER 12 int main() { int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); if (fd < 0) { perror("socket"); return 1; } struct sockaddr_nl src_addr, dest_addr; memset(&src_addr, 0, sizeof(src_addr)); src_addr.nl_family = AF_NETLINK; src_addr.nl_pid = getpid(); memset(&dest_addr, 0, sizeof(dest_addr)); dest_addr.nl_family = AF_NETLINK; dest_addr.nl_pid = 0; // Kernel bind(fd, (struct sockaddr*)&src_addr, sizeof(src_addr)); // Buffer for netlink message char buffer[4096]; struct nlmsghdr *nlh = (struct nlmsghdr *)buffer; memset(buffer, 0, 4096); nlh->nlmsg_len = NLMSG_LENGTH(0); // Placeholder nlh->nlmsg_pid = getpid(); nlh->nlmsg_flags = 0; // Malicious payload construction would go here. // Specifically crafting CTA_PROTOINFO_SCTP_STATE or related attributes // to bypass validation and trigger the OOB access described in the CVE. // Sending the message sendto(fd, nlh, nlh->nlmsg_len, 0, (struct sockaddr*)&dest_addr, sizeof(dest_addr)); close(fd); return 0; }

{"cve": {"id": "CVE-2026-31407", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-06T08:16:38.623", "lastModified": "2026-05-20T16:22:08.980", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: conntrack: add missing netlink policy validations\n\nHyunwoo Kim reports out-of-bounds access in sctp and ctnetlink.\n\nThese attributes are used by the kernel without any validation.\nExtend the netlink policies accordingly.\n\nQuoting the reporter:\n nlattr_to_sctp() assigns the user-supplied CTA_PROTOINFO_SCTP_STATE\n value directly to ct->proto.sctp.state without checking that it is\n within the valid range. [..]\n\n and: ... with exp->dir = 100, the access at\n ct->master->tuplehash[100] reads 5600 bytes past the start of a\n 320-byte nf_conn object, causing a slab-out-of-bounds read confirmed by\n UBSAN."}], "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": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.27", "versionEndExcluding": "6.6.136", "matchCriteriaId": "B3457033-D01A-43C8-836D-8E21A577B7A5"}, {"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": "6.19.10", "matchCriteriaId": "96D34333-38BE-4414-9E79-6EB764329581"}, {"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"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/0fbae1e74493d5a160a70c51aeba035d8266ea7d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/67c53c1978cef3c504237275e39c857e2f6af56e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9174d28f3f15d8c4962f5980c0be167633880443", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c5e918390002edf0cff80a0e7ce1f86f16a9507c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/f900e1d77ee0ef87bfb5ab3fe60f0b3d8ad5ba05", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}