{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-31513", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-31513" ], "published": "2026-04-22T13:57:42Z", "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.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.12.75-1+rpt1~bookworm" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.75+rpt-rpi-2712", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v6", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v7", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v7l", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8", "binary_version": "1:6.12.75-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8-rt", "binary_version": "1:6.12.75-1+rpt1~bookworm" } ] }, "database_specific": { "per_version": { "1:6.12.75-1+rpt1~bookworm": { "linux_commit": "89050b1059997d38d55462b323b099a6436dc10d", "upstream_version": "6.12.75", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.80" } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.12.75-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.75+rpt-rpi-2712", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v6", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v7", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8", "binary_version": "1:6.12.75-1+rpt1" }, { "binary_name": "linux-image-6.12.75+rpt-rpi-v8-rt", "binary_version": "1:6.12.75-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.12.75-1+rpt1": { "linux_commit": "89050b1059997d38d55462b323b099a6436dc10d", "upstream_version": "6.12.75", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.80" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-31513" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/5b35f8211a913cfe7ab9d54fa36a272d2059a588" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9d87cb22195b2c67405f5485d525190747ad5493" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T13:16:28Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 8.1, "cvss_v3_severity": "High", "scenario": "AV:A - The vulnerable code is reached by a Bluetooth LE L2CAP signaling packet from a nearby Bluetooth peer, so exploitation requires adjacent radio proximity rather than internet routing or local code execution.\nAC:L - The attacker only needs to send a malformed Enhanced Credit Based Connection Request with more than 5 SCIDs; the bad length is used deterministically before the bounds check.\nPR:N - The vulnerable path is reached before PSM lookup and before `smp_sufficient_security()`, so no pairing, authentication, service authorization, or local privilege is required.\nUI:N - Once the target is reachable over Bluetooth LE, the malformed signaling request is processed by the kernel without requiring a victim user action.\nS:U - The impact is within the kernel Bluetooth stack on the same host security authority; this is not a cross-VM, IOMMU, or sandbox boundary escape by itself.\nC:H - The oversized response length causes `l2cap_send_cmd()` to copy beyond an 18-byte stack buffer into an outbound L2CAP response, exposing attacker-sized kernel stack contents rather than a strictly bounded few bytes.\nI:N - The bug is an out-of-bounds read used to build a response packet; it does not provide an out-of-bounds write or direct modification of kernel data.\nA:H - The same malformed packet triggers a demonstrated KASAN stack-out-of-bounds panic, and a sufficiently large kernel stack read can reasonably crash the kernel even outside KASAN builds." } } }