{"schema":"threatline.record/2","record":{"id":"CVE-2026-98455","aliases":[],"summary":"Bluetooth: RFCOMM: fix NULL dereference of dlc->session in RFCOMM_CONNINFO","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: fix NULL dereference of dlc->session in RFCOMM_CONNINFO\n\nThe RFCOMM_CONNINFO getsockopt handler accepts a socket that is not\nconnected as long as deferred setup is enabled:\n\n\tif (sk->sk_state != BT_CONNECTED &&\n\t\t\t\t!rfcomm_pi(sk)->dlc->defer_setup) {\n\t\terr = -ENOTCONN;\n\t\tbreak;\n\t}\n\tl2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;\n\ndlc->defer_setup is set in rfcomm_sock_init() when rfcomm_connect_ind()\ncreates a child socket for an incoming connection on a listening socket\nthat has BT_DEFER_SETUP enabled. It is never cleared afterwards. The\nsession, however, can go away underneath it.\n\nrfcomm_recv_disc() forces the dlc state before tearing it down:\n\n\td->state = BT_CLOSED;\n\t__rfcomm_dlc_close(d, err);\n\nThe RFCOMM_DEFER_SETUP early return in __rfcomm_dlc_close() only covers\nBT_CONNECT, BT_CONFIG, BT_OPEN and BT_CONNECT2, so with the state\nalready BT_CLOSED that switch does not match and the function falls\nthrough to rfcomm_dlc_unlink(), which sets d->session = NULL, while\nd->defer_setup stays 1.\n\nA getsockopt(SOL_RFCOMM, RFCOMM_CONNINFO) on the accepted socket after\nthat point therefore skips the -ENOTCONN path -- sk->sk_state is\nBT_CLOSED, but dlc->defer_setup is still set -- and dereferences the\nNULL session. No race is needed: once the DISC has been processed, the\ndereference is unconditional.\n\nReproduced on a KASAN kernel under QEMU with a BR/EDR peer emulated over\n/dev/vhci: the peer brings up an ACL link, opens L2CAP on the RFCOMM\nPSM, starts a session and sends SABM for a channel bound with\nBT_DEFER_SETUP, and sends DISC for that dlci after the socket has been\naccepted. getsockopt(SOL_RFCOMM, RFCOMM_CONNINFO) on the accepted\nsocket then hits:\n\n Oops: general protection fault, probably for non-canonical address\n 0xdffffc0000000002: 0000 [#1] SMP KASAN PTI\n KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]\n CPU: 1 UID: 0 PID: 150 Comm: init Tainted: G B 7.3.0-rc3-g5dd1818b15d9\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)\n RIP: 0010:rfcomm_sock_getsockopt+0x529/0x780\n Call Trace:\n  <TASK>\n  do_sock_getsockopt+0x3ad/0x7d0\n  __sys_getsockopt+0x10e/0x1b0\n  __x64_sys_getsockopt+0xc2/0x160\n  do_syscall_64+0xda/0x4b0\n  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  </TASK>\n\n0x10 is the offset of sock in struct rfcomm_session;\nrfcomm_sock_getsockopt_old() is inlined into rfcomm_sock_getsockopt().\n\nCommit 43a556b2fd43 (\"Bluetooth: RFCOMM: take rfcomm_mutex for the\ndeferred setup accept\") fixed the same \"a remote DISC clears the session\nwhile deferred setup is still flagged\" problem in rfcomm_dlc_accept();\nthis is the remaining instance of it, in the getsockopt path.\n\nDeferred setup only leaves a socket usable here once it has reached\nBT_CONNECT2, so restrict the exception to that state and check that a\nsession is actually present before following it.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98455","source_modified_at":"2026-10-19T09:19:50.740Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"c3aee3fc1287c8a555baf3895959087cb0c33fe8","status":"affected","versionType":"git"},{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"4bf5ca47203049ce3648f750a53dcdc98bcc9e3e","status":"affected","versionType":"git"},{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"1c4f7e1177da2f229be04139c27e5370a1cfba52","status":"affected","versionType":"git"},{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"84ae3cfd7d3a63591a2eb4faa24faf678c6708aa","status":"affected","versionType":"git"},{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"c7362f6a18ed167f52f08ce25eeec8a7818c5004","status":"affected","versionType":"git"},{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"8f5b30cc12c409ff62891e47ed51e6bf0945a3ea","status":"affected","versionType":"git"},{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"005b23d9e324fe5d0acbcfa70c625f2e81189046","status":"affected","versionType":"git"},{"version":"bb23c0ab824653be4aa7dfca15b07b3059717004","lessThan":"46f8ffd0a1f1eb6cbc94946a92c11ef601e228a1","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98455","source_modified_at":"2026-10-19T09:19:50.740Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"2.6.30","status":"affected"},{"version":"0","lessThan":"2.6.30","status":"unaffected","versionType":"semver"},{"version":"5.10.271","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98455","source_modified_at":"2026-10-19T09:19:50.740Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"4bf5ca47203049ce3648f750a53dcdc98bcc9e3e","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98455","source_modified_at":"2026-10-19T09:19:50.740Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"1c4f7e1177da2f229be04139c27e5370a1cfba52","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98455","source_modified_at":"2026-10-19T09:19:50.740Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"84ae3cfd7d3a63591a2eb4faa24faf678c6708aa","basis":"first unaffected version stated in the CVE record"},{"source":"CVE 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record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00176,"percentile":0.0683,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:15:04.988Z","modified_at":"2026-10-19T09:19:50.740Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98455","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:19:50.740Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98455","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/c3aee3fc1287c8a555baf3895959087cb0c33fe8"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/4bf5ca47203049ce3648f750a53dcdc98bcc9e3e"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/1c4f7e1177da2f229be04139c27e5370a1cfba52"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/84ae3cfd7d3a63591a2eb4faa24faf678c6708aa"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/c7362f6a18ed167f52f08ce25eeec8a7818c5004"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/8f5b30cc12c409ff62891e47ed51e6bf0945a3ea"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/005b23d9e324fe5d0acbcfa70c625f2e81189046"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/46f8ffd0a1f1eb6cbc94946a92c11ef601e228a1"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:19:50.740Z","content_hash":"4aa1dbb99402fea6fd9192eb24bcd2ef69e6861cccc5d386c180b1fc6352bfa0"}}