{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31513", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.107Z", "datePublished": "2026-04-22T13:54:30.835Z", "dateUpdated": "2026-08-05T12:23:12.375Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:23:12.375Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/l2cap_core.c" ], "versions": [ { "version": "935f324e4b2461df2cf7f02b4195082b4304c708", "lessThan": "c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc", "status": "affected", "versionType": "git" }, { "version": "e981a9392800ce2c5bca196a6ab2c55e9370efaa", "lessThan": "5b35f8211a913cfe7ab9d54fa36a272d2059a588", "status": "affected", "versionType": "git" }, { "version": "f3fdf2e7276a3edc5df55454275da20eac186970", "lessThan": "a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b", "status": "affected", "versionType": "git" }, { "version": "c28d2bff70444a85b3b86aaf241ece9408c7858c", "lessThan": "9d87cb22195b2c67405f5485d525190747ad5493", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/l2cap_core.c" ], "versions": [ { "version": "6.12.75", "lessThan": "6.12.80", "status": "affected", "versionType": "semver" }, { "version": "6.18.16", "lessThan": "6.18.21", "status": "affected", "versionType": "semver" }, { "version": "6.19.6", "lessThan": "6.19.11", "status": "affected", "versionType": "semver" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.75", "versionEndExcluding": "6.12.80" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.16", "versionEndExcluding": "6.18.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19.6", "versionEndExcluding": "6.19.11" } ] } ] } ], "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" } ], "title": "Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req", "x_generator": { "engine": "bippy-1.2.0" } } } }