{"id":"CVE-2026-31513","title":"Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req","summary":"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 mal…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 935f324e4b2461df2cf7f02b4195082b4304c708 < c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc","Linux >= e981a9392800ce2c5bca196a6ab2c55e9370efaa < 5b35f8211a913cfe7ab9d54fa36a272d2059a588","Linux >= f3fdf2e7276a3edc5df55454275da20eac186970 < a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b","Linux >= c28d2bff70444a85b3b86aaf241ece9408c7858c < 9d87cb22195b2c67405f5485d525190747ad5493","Linux >= 6.12.75 < 6.12.80","Linux >= 6.18.16 < 6.18.21","Linux >= 6.19.6 < 6.19.11"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T15:10:31.040486Z"},"published":"2026-04-22","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:20:14.252Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31513","references":[{"url":"https://git.kernel.org/stable/c/c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc"},{"url":"https://git.kernel.org/stable/c/5b35f8211a913cfe7ab9d54fa36a272d2059a588"},{"url":"https://git.kernel.org/stable/c/a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b"},{"url":"https://git.kernel.org/stable/c/9d87cb22195b2c67405f5485d525190747ad5493"}],"tags":["cve.org"],"epss":0.00385,"epssPercentile":0.31024,"ingestedAt":"2026-10-16T17:24:46.658Z","slug":"CVE-2026-31513","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 935f324e4b2461df2cf7f02b4195082b4304c708 < c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc`\n- `Linux >= e981a9392800ce2c5bca196a6ab2c55e9370efaa < 5b35f8211a913cfe7ab9d54fa36a272d2059a588`\n- `Linux >= f3fdf2e7276a3edc5df55454275da20eac186970 < a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b`\n- `Linux >= c28d2bff70444a85b3b86aaf241ece9408c7858c < 9d87cb22195b2c67405f5485d525190747ad5493`\n- `Linux >= 6.12.75 < 6.12.80`\n- `Linux >= 6.18.16 < 6.18.21`\n- `Linux >= 6.19.6 < 6.19.11`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}