CVE-2026-74540

{"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": "2026-10-16T19:05:54.604Z"}, "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 \u2192 l2cap_recv_acldata \u2192 l2cap_le_sig_channel \u2192 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"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-74540", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T18:59:42.755795Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:05:54.604Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-74540", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T18:59:42.755795Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T18:59:43.659Z"}}], "cna": {"title": "Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 8.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}, "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 \u2192 l2cap_recv_acldata \u2192 l2cap_le_sig_channel \u2192 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": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "15d6c2367217a6a20b1abae9f38ded716bf620f1", "versionType": "git"}, {"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "1818180fe12d6cec7a437bc59cde8efdf6b10250", "versionType": "git"}, {"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "8325eafb38c3dee5af329266393763693d17381b", "versionType": "git"}, {"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "fd4c1e301bdec60a40728ea37de531cbccda501a", "versionType": "git"}, {"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "522b730c62c53a1981604fd73524697fd347830d", "versionType": "git"}, {"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136", "versionType": "git"}, {"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "09f447accc2570751e7d17f0dc0788b40d3edade", "versionType": "git"}, {"status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "lessThan": "c4740e7f23ff9a8210198d8b4703259e21b9f69d", "versionType": "git"}], "programFiles": ["net/bluetooth/l2cap_core.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "3.14"}, {"status": "unaffected", "version": "0", "lessThan": "3.14", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.265", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.216", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.183", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.151", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.103", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.44", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.1.8", "versionType": "semver", "lessThanOrEqual": "7.1.*"}, {"status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/bluetooth/l2cap_core.c"], "defaultStatus": "affected"}], "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"}], "x_generator": {"engine": "bippy-1.2.0"}, "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."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.265", "versionStartIncluding": "3.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.216", "versionStartIncluding": "3.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.183", "versionStartIncluding": "3.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.151", "versionStartIncluding": "3.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.103", "versionStartIncluding": "3.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.44", "versionStartIncluding": "3.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.1.8", "versionStartIncluding": "3.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2", "versionStartIncluding": "3.14"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:38:32.306Z"}}}, "cveMetadata": {"cveId": "CVE-2026-74540", "state": "PUBLISHED", "dateUpdated": "2026-10-16T19:05:54.604Z", "dateReserved": "2026-08-15T05:44:03.913Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-08-15T12:27:51.522Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/bluetooth/l2cap_core.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "15d6c2367217a6a20b1abae9f38ded716bf620f1", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}, {"lessThan": "1818180fe12d6cec7a437bc59cde8efdf6b10250", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}, {"lessThan": "8325eafb38c3dee5af329266393763693d17381b", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}, {"lessThan": "fd4c1e301bdec60a40728ea37de531cbccda501a", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}, {"lessThan": "522b730c62c53a1981604fd73524697fd347830d", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}, {"lessThan": "58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}, {"lessThan": "09f447accc2570751e7d17f0dc0788b40d3edade", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}, {"lessThan": "c4740e7f23ff9a8210198d8b4703259e21b9f69d", "status": "affected", "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/bluetooth/l2cap_core.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "3.14"}, {"lessThan": "3.14", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.265", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.216", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.183", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.151", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.103", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.44", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.8", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-74540", "lastModified": "2026-10-16T20:17:36.427", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-74540", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T18:59:42.755795Z", "version": "2.0.3"}}]}, "published": "2026-08-15T13:17:59.337", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp", "id": "2517013", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2517013"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nBluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp\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.\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.\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.", "A flaw was found in the Linux kernel's Bluetooth L2CAP (Logical Link Control and Adaptation Protocol) component. A use-after-free (UAF) vulnerability exists in the `l2cap_le_connect_rsp()` function, where a channel can be freed while still being referenced. This can be triggered by a remote disconnect, potentially allowing a remote attacker to corrupt memory and achieve arbitrary code execution or cause a denial of service."], "name": "CVE-2026-74540", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74540\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74540\nhttps://lore.kernel.org/linux-cve-announce/2026081548-CVE-2026-74540-5b1d@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1496dee9cbde2a62821f4441dadb0d3360f60c3,fd4c1e301bdec60a40728ea37de531cbccda501a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1496dee9cbde2a62821f4441dadb0d3360f60c3,522b730c62c53a1981604fd73524697fd347830d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1496dee9cbde2a62821f4441dadb0d3360f60c3,58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1496dee9cbde2a62821f4441dadb0d3360f60c3,09f447accc2570751e7d17f0dc0788b40d3edade)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1496dee9cbde2a62821f4441dadb0d3360f60c3,c4740e7f23ff9a8210198d8b4703259e21b9f69d)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "3.14"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,3.14)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.151,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.103,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.44,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.8,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc6,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-15T15:15:03.212813+00:00", "updated": "2026-08-22T03:45:03.674719+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}