{"id":"CVE-2023-53297","state":"PUBLISHED","title":"Bluetooth: L2CAP: fix \"bad unlock balance\" in l2cap_disconnect_rsp","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix \"bad unlock balance\" in l2cap_disconnect_rsp\n\nconn->chan_lock isn't acquired before l2cap_get_chan_by_scid,\nif l2cap_get_chan_by_scid returns NULL, then 'bad unlock balance'\nis triggered.","publishedAt":"2025-09-16T08:11:29.283Z","updatedAt":"2026-08-05T09:13:24.678Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f2d38e77aa5f3effc143e7dd24da8acf02925958","status":"affected","lessThan":"5f352a56f0e607e6ff539cbf12156bfd8af232be","versionType":"git"},{"version":"1351551aa9058e07a20a27a158270cf84fcde621","status":"affected","lessThan":"6a27762340ad08643de3bc17fe1646ea489ca2e2","versionType":"git"},{"version":"c02421992505c95c7f3c9ad59ee35e22eac60988","status":"affected","lessThan":"2112c4c47d36bc5aba3ddeb9afedce6ae6a67e7d","versionType":"git"},{"version":"d9ba36c22a7bb09d6bac4cc2f243eff05da53f43","status":"affected","lessThan":"55410a9144c76ecda126e6cdec556dfcd8f343b2","versionType":"git"},{"version":"ac6725a634f7e8c0330610a8527f20c730b61115","status":"affected","lessThan":"116b9c002c894097adc2b8684db2d1da4229ed46","versionType":"git"},{"version":"348d446762e7c70778df8bafbdf3fa0df2123f58","status":"affected","lessThan":"fd269a0435f8e9943b7a57c5a59688848d42d449","versionType":"git"},{"version":"a2a9339e1c9deb7e1e079e12e27a0265aea8421a","status":"affected","lessThan":"5134556c9be582793f30695c09d18a26fe1ff2d7","versionType":"git"},{"version":"a2a9339e1c9deb7e1e079e12e27a0265aea8421a","status":"affected","lessThan":"25e97f7b1866e6b8503be349eeea44bb52d661ce","versionType":"git"},{"version":"d82a439c3cfdb28aa7e82e2e849c5c4dd9fca284","status":"affected","versionType":"git"},{"version":"4.14.313","status":"affected","lessThan":"4.14.316","versionType":"semver"},{"version":"4.19.281","status":"affected","lessThan":"4.19.284","versionType":"semver"},{"version":"5.4.241","status":"affected","lessThan":"5.4.244","versionType":"semver"},{"version":"5.10.178","status":"affected","lessThan":"5.10.181","versionType":"semver"},{"version":"5.15.108","status":"affected","lessThan":"5.15.113","versionType":"semver"},{"version":"6.1.25","status":"affected","lessThan":"6.1.30","versionType":"semver"},{"version":"6.2.12","status":"affected","lessThan":"6.3","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"4.14.316","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.284","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.244","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.181","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.113","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.30","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.3.4","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c"]}],"references":["https://git.kernel.org/stable/c/5f352a56f0e607e6ff539cbf12156bfd8af232be","https://git.kernel.org/stable/c/6a27762340ad08643de3bc17fe1646ea489ca2e2","https://git.kernel.org/stable/c/2112c4c47d36bc5aba3ddeb9afedce6ae6a67e7d","https://git.kernel.org/stable/c/55410a9144c76ecda126e6cdec556dfcd8f343b2","https://git.kernel.org/stable/c/116b9c002c894097adc2b8684db2d1da4229ed46","https://git.kernel.org/stable/c/fd269a0435f8e9943b7a57c5a59688848d42d449","https://git.kernel.org/stable/c/5134556c9be582793f30695c09d18a26fe1ff2d7","https://git.kernel.org/stable/c/25e97f7b1866e6b8503be349eeea44bb52d661ce"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53297.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53297","state":"PUBLISHED","datePublished":"2025-09-16T08:11:29.283Z","dateUpdated":"2026-08-05T09:13:24.678Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-09-16T08:09:37.993Z"},"containers":{"cna":{"title":"Bluetooth: L2CAP: fix \"bad unlock balance\" in l2cap_disconnect_rsp","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix \"bad unlock balance\" in l2cap_disconnect_rsp\n\nconn->chan_lock isn't acquired before l2cap_get_chan_by_scid,\nif l2cap_get_chan_by_scid returns NULL, then 'bad unlock balance'\nis triggered."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f2d38e77aa5f3effc143e7dd24da8acf02925958","status":"affected","lessThan":"5f352a56f0e607e6ff539cbf12156bfd8af232be","versionType":"git"},{"version":"1351551aa9058e07a20a27a158270cf84fcde621","status":"affected","lessThan":"6a27762340ad08643de3bc17fe1646ea489ca2e2","versionType":"git"},{"version":"c02421992505c95c7f3c9ad59ee35e22eac60988","status":"affected","lessThan":"2112c4c47d36bc5aba3ddeb9afedce6ae6a67e7d","versionType":"git"},{"version":"d9ba36c22a7bb09d6bac4cc2f243eff05da53f43","status":"affected","lessThan":"55410a9144c76ecda126e6cdec556dfcd8f343b2","versionType":"git"},{"version":"ac6725a634f7e8c0330610a8527f20c730b61115","status":"affected","lessThan":"116b9c002c894097adc2b8684db2d1da4229ed46","versionType":"git"},{"version":"348d446762e7c70778df8bafbdf3fa0df2123f58","status":"affected","lessThan":"fd269a0435f8e9943b7a57c5a59688848d42d449","versionType":"git"},{"version":"a2a9339e1c9deb7e1e079e12e27a0265aea8421a","status":"affected","lessThan":"5134556c9be582793f30695c09d18a26fe1ff2d7","versionType":"git"},{"version":"a2a9339e1c9deb7e1e079e12e27a0265aea8421a","status":"affected","lessThan":"25e97f7b1866e6b8503be349eeea44bb52d661ce","versionType":"git"},{"version":"d82a439c3cfdb28aa7e82e2e849c5c4dd9fca284","status":"affected","versionType":"git"},{"version":"4.14.313","status":"affected","lessThan":"4.14.316","versionType":"semver"},{"version":"4.19.281","status":"affected","lessThan":"4.19.284","versionType":"semver"},{"version":"5.4.241","status":"affected","lessThan":"5.4.244","versionType":"semver"},{"version":"5.10.178","status":"affected","lessThan":"5.10.181","versionType":"semver"},{"version":"5.15.108","status":"affected","lessThan":"5.15.113","versionType":"semver"},{"version":"6.1.25","status":"affected","lessThan":"6.1.30","versionType":"semver"},{"version":"6.2.12","status":"affected","lessThan":"6.3","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"4.14.316","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.284","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.244","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.181","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.113","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.30","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.3.4","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5f352a56f0e607e6ff539cbf12156bfd8af232be"},{"url":"https://git.kernel.org/stable/c/6a27762340ad08643de3bc17fe1646ea489ca2e2"},{"url":"https://git.kernel.org/stable/c/2112c4c47d36bc5aba3ddeb9afedce6ae6a67e7d"},{"url":"https://git.kernel.org/stable/c/55410a9144c76ecda126e6cdec556dfcd8f343b2"},{"url":"https://git.kernel.org/stable/c/116b9c002c894097adc2b8684db2d1da4229ed46"},{"url":"https://git.kernel.org/stable/c/fd269a0435f8e9943b7a57c5a59688848d42d449"},{"url":"https://git.kernel.org/stable/c/5134556c9be582793f30695c09d18a26fe1ff2d7"},{"url":"https://git.kernel.org/stable/c/25e97f7b1866e6b8503be349eeea44bb52d661ce"}],"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 bug is reached only by processing an L2CAP Disconnect Response on the BR/EDR or LE signaling CID (hci_rx_work → l2cap_recv_acldata → l2cap_recv_frame → l2cap_disconnect_rsp), which requires a Bluetooth peer within radio range; kernel guidance maps Bluetooth to Adjacent.\nAC:L - The attacker reliably triggers the bad unlock by sending DISCONN_RSP with a nonexistent SCID, and can also drive concurrent chan_lock holders (channel timers, connect/disconnect churn) so the premature unlock races list walks; both sides are attacker-influenced with no uncontrollable condition.\nPR:N - l2cap_recv_frame dispatches CID 0x0001/0x0005 to the signaling handlers with no pairing, encryption, or security-level check, so an unauthenticated in-range device can send the triggering PDU on an established ACL/LE link.\nUI:N - No victim action is required; once the host is connectable/advertising with Bluetooth enabled (default on phones, cars, and laptops), the crafted PDU is processed automatically by hci_rx_work.\nS:U - Impact stays inside the host kernel Bluetooth/L2CAP authority; this is standard kernel memory-safety compromise, not a VM, IOMMU, or sandbox boundary crossing.\nC:H - Unlocking conn->chan_lock while another context (e.g. l2cap_chan_timeout) holds it exposes conn->chan_l to unsynchronized list manipulation and use-after-free of struct l2cap_chan, which per guidance enables heap reuse and arbitrary kernel read primitives.\nI:H - The same premature unlock races l2cap_chan_del/list walks against concurrent channel ops, yielding use-after-free write and function-pointer hijack primitives via sprayed reclaimed channel objects.\nA:H - The defect produces a lockdep \"bad unlock balance\" WARNING (panic under panic_on_warn) and, when it unlocks under a concurrent holder, use-after-free crashes/oopses on the channel list that an adjacent peer can re-trigger at 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ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.5,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"id":"CVE-2023-53297","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-01-14T18:12:33.884627Z"}}}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","description":"CWE-noinfo Not enough information"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-01-14T18:12:56.873Z"}}]}}}