{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74540", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.913Z", "datePublished": "2026-08-15T12:27:51.522Z", "dateUpdated": "2026-08-19T16:38:32.306Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:38:32.306Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp\n\nl2cap_le_connect_rsp() obtains a channel via\n__l2cap_get_chan_by_ident() but neither holds a reference nor uses\nl2cap_chan_hold_unless_zero() before locking and operating on it.\nA concurrent l2cap_chan_del() triggered by a remote disconnect can\nfree the channel between the lookup and l2cap_chan_lock(), causing\na use-after-free.\n\nThe BR/EDR counterpart l2cap_connect_rsp() and the sibling handler\nl2cap_le_command_rej() already use l2cap_chan_hold_unless_zero()\nto safely hold a reference, but l2cap_le_connect_rsp() was left\nunprotected.\n\nFix by adding l2cap_chan_hold_unless_zero() after the ident lookup\nand l2cap_chan_put() on the exit path, consistent with other L2CAP\nresponse handlers." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:A - The vulnerability is reached when the kernel processes an incoming L2CAP LE Connect Response over an established Bluetooth LE ACL link (HCI ACL receive → l2cap_recv_acldata → l2cap_le_sig_channel → l2cap_le_connect_rsp), requiring radio proximity rather than routable Internet access.\nAC:L - The remote Bluetooth peer controls both sides of the race by sending L2CAP_LE_CONN_RSP while concurrently triggering channel teardown via L2CAP DISCONN_REQ or HCI disconnect, freeing the channel between __l2cap_get_chan_by_ident() and l2cap_chan_lock() without attacker-uncontrollable timing.\nPR:N - No local privileges on the victim are required; exploitation needs only a nearby attacker with an established LE Bluetooth connection sending crafted L2CAP signaling packets, with no root, CAP_NET_ADMIN, or user-namespace capability on the target host.\nUI:N - On phones, wearables, automotive, and IoT deployments, paired or background Bluetooth clients routinely auto-initiate L2CAP credit-based connections without per-attack user confirmation once an LE link is up, enabling trigger of the pending outgoing connect path.\nS:U - Impact is confined to kernel memory and privileges on the Bluetooth-connected host; there is no VM guest-to-host escape, sandbox breakout, or IOMMU/DMA boundary crossing, so security scope remains unchanged per kernel CVSS guidance.\nC:H - Use-after-free of heap-allocated struct l2cap_chan allows attacker-controlled reuse of freed slab memory, enabling disclosure of kernel heap contents and pointers through corrupted channel fields accessed after premature free.\nI:H - The UAF window writes channel state (ident, dcid, mtu, credits) and invokes chan->ops function pointers (ready, teardown) on freed memory, enabling heap spraying and control-flow hijack for arbitrary kernel code execution.\nA:H - Operating on a freed l2cap_chan can immediately kernel-oops or panic from corrupt mutex/state during lock/unlock and callback dispatch; UAF in softirq L2CAP processing inherently threatens full system availability." } ] } ], "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": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "15d6c2367217a6a20b1abae9f38ded716bf620f1", "status": "affected", "versionType": "git" }, { "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "1818180fe12d6cec7a437bc59cde8efdf6b10250", "status": "affected", "versionType": "git" }, { "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "8325eafb38c3dee5af329266393763693d17381b", "status": "affected", "versionType": "git" }, { "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "fd4c1e301bdec60a40728ea37de531cbccda501a", "status": "affected", "versionType": "git" }, { "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "522b730c62c53a1981604fd73524697fd347830d", "status": "affected", "versionType": "git" }, { "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136", "status": "affected", "versionType": "git" }, { "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "09f447accc2570751e7d17f0dc0788b40d3edade", "status": "affected", "versionType": "git" }, { "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "c4740e7f23ff9a8210198d8b4703259e21b9f69d", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/l2cap_core.c" ], "versions": [ { "version": "3.14", "status": "affected" }, { "version": "0", "lessThan": "3.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.151", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.103", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.44", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.8", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "6.6.151" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "6.12.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "6.18.44" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "7.1.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1" }, { "url": "https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250" }, { "url": "https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b" }, { "url": "https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a" }, { "url": "https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d" }, { "url": "https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136" }, { "url": "https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade" }, { "url": "https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d" } ], "title": "Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp", "x_generator": { "engine": "bippy-1.2.0" } } } }