{"id":"CVE-2026-31513","summary":"Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req\n\nSyzbot reported a KASAN stack-out-of-bounds read in l2cap_build_cmd()\nthat is triggered by a malformed Enhanced Credit Based Connection Request.\n\nThe vulnerability stems from l2cap_ecred_conn_req(). The function allocates\na local stack buffer (`pdu`) designed to hold a maximum of 5 Source Channel\nIDs (SCIDs), totaling 18 bytes. When an attacker sends a request with more\nthan 5 SCIDs, the function calculates `rsp_len` based on this unvalidated\n`cmd_len` before checking if the number of SCIDs exceeds\nL2CAP_ECRED_MAX_CID.\n\nIf the SCID count is too high, the function correctly jumps to the\n`response` label to reject the packet, but `rsp_len` retains the\nattacker's oversized value. Consequently, l2cap_send_cmd() is instructed\nto read past the end of the 18-byte `pdu` buffer, triggering a\nKASAN panic.\n\nFix this by moving the assignment of `rsp_len` to after the `num_scid`\nboundary check. If the packet is rejected, `rsp_len` will safely\nremain 0, and the error response will only read the 8-byte base header\nfrom the stack.","modified":"2026-07-15T01:48:56.868901472Z","published":"2026-04-22T13:54:30.835Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31513.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5b35f8211a913cfe7ab9d54fa36a272d2059a588"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9d87cb22195b2c67405f5485d525190747ad5493"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31513.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31513"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"935f324e4b2461df2cf7f02b4195082b4304c708"},{"fixed":"c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"e981a9392800ce2c5bca196a6ab2c55e9370efaa"},{"fixed":"5b35f8211a913cfe7ab9d54fa36a272d2059a588"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f3fdf2e7276a3edc5df55454275da20eac186970"},{"fixed":"a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c28d2bff70444a85b3b86aaf241ece9408c7858c"},{"fixed":"9d87cb22195b2c67405f5485d525190747ad5493"}]}],"versions":["v6.12.79","v6.12.78","v6.12.77","v6.12.76","v6.12.75","v6.18.20","v6.18.19","v6.18.18","v6.18.17","v6.18.16","v6.19.10","v6.19.9","v6.19.8","v6.19.7","v6.19.6"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31513.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.75"},{"fixed":"6.12.80"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.18.16"},{"fixed":"6.18.21"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.6"},{"fixed":"6.19.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31513.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"}]}