{"id":"CVE-2026-74540","summary":"Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp","details":"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.","modified":"2026-08-21T03:30:21.751193723Z","published":"2026-08-15T12:27:51.522Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74540.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade"},{"type":"WEB","url":"https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250"},{"type":"WEB","url":"https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74540.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74540"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f1496dee9cbde2a62821f4441dadb0d3360f60c3"},{"fixed":"15d6c2367217a6a20b1abae9f38ded716bf620f1"},{"fixed":"1818180fe12d6cec7a437bc59cde8efdf6b10250"},{"fixed":"8325eafb38c3dee5af329266393763693d17381b"},{"fixed":"fd4c1e301bdec60a40728ea37de531cbccda501a"},{"fixed":"522b730c62c53a1981604fd73524697fd347830d"},{"fixed":"58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136"},{"fixed":"09f447accc2570751e7d17f0dc0788b40d3edade"},{"fixed":"c4740e7f23ff9a8210198d8b4703259e21b9f69d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74540.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.14.0"},{"fixed":"5.10.265"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.216"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.183"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.151"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.103"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.44"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74540.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}