{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-80819", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-80819", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-09-04T15:13:40.309Z", "updatedAt": "2026-10-19T08:44:12.945Z", "importedAt": "2026-10-24T01:58:30.346Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "Bluetooth: RFCOMM: take rfcomm_mutex for the deferred setup accept", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: take rfcomm_mutex for the deferred setup accept\n\nrfcomm_sock_recvmsg() completes a deferred setup by calling\nrfcomm_dlc_accept() without holding any RFCOMM lock:\n\n\tif (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) {\n\t\trfcomm_dlc_accept(d);\n\t\treturn 0;\n\t}\n\nand rfcomm_dlc_accept() dereferences the session on its first line:\n\n\tstruct sock *sk = d->session->sock->sk;\n\nEvery other path that touches d->session runs under rfcomm_mutex:\nrfcomm_dlc_open(), rfcomm_dlc_close(), rfcomm_dlc_exists(),\nrfcomm_dlc_send_rpn(), and the RFCOMM thread through\nrfcomm_process_sessions(). rfcomm_connect_ind() is even documented as\n\"called under rfcomm_lock()\". This call site is the only one that skips\nit.\n\nThe RFCOMM_DEFER_SETUP bit looks like it serialises the accept against\nteardown, since __rfcomm_dlc_close() returns early when it wins the\ntest_and_clear. But rfcomm_recv_disc() forces the state first:\n\n\td->state = BT_CLOSED;\n\t__rfcomm_dlc_close(d, err);\n\nand the early return only covers BT_CONNECT, BT_CONFIG, BT_OPEN and\nBT_CONNECT2. With the state already BT_CLOSED that switch does not\nmatch, the bit is never consulted, and __rfcomm_dlc_close() falls\nthrough to rfcomm_dlc_unlink(), which sets d->session = NULL.\n\nSo a remote DISC on a deferred dlc clears the session while leaving\nRFCOMM_DEFER_SETUP set. The next recvmsg() then passes the\ntest_and_clear and dereferences a NULL session. No timing window is\nneeded: once the DISC has been processed, the dereference is\nunconditional.\n\nGive rfcomm_dlc_accept() the same shape as rfcomm_dlc_open() and\nrfcomm_dlc_close(): an exported wrapper that takes rfcomm_mutex and\nre-checks the session, around a __rfcomm_dlc_accept() that the two\nin-core callers, which already hold the mutex, keep using.\n\nReproduced on a KASAN + PROVE_LOCKING kernel with a BR/EDR peer emulated\nover /dev/vhci: the peer brings up an ACL link, opens L2CAP on the\nRFCOMM PSM, starts a session, opens a dlc on a channel bound with\nBT_DEFER_SETUP, and sends DISC after the socket is accepted. recv() on\nthe accepted socket then hits:\n\n Oops: general protection fault\n KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]\n RIP: 0010:rfcomm_dlc_accept+0x54/0x350\n Call Trace:\n rfcomm_sock_recvmsg+0x1cd/0x230\n sock_recvmsg+0x166/0x1c0\n __sys_recvfrom+0x20d/0x300\n\n0x10 is the offset of sock in struct rfcomm_session. With this patch the\nsame run completes with recv() returning 0 and no report, and lockdep\nstays quiet, confirming rfcomm_mutex is still taken before lock_sock on\nthis path as it is on the thread side.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "d8d686dd5662a7c4745e4515f1237a9f3b7df181" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "eb71d5a1ea8ff2683e394b48ae3cd676037ab4c2" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "56f0aa75c7640e46397ef73bea251fcbef9150c0" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "362726c9c6e56eea4262109183e49868c39ccd3a" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "825b95561d7b7c393df9e7bc295451aaeadc3d18" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "d4b1a13b1eff2e80925c7368ffdeaaa50cba93df" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "355bfd57ca4ca881c6eb03ca813b440a094b1f44" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "b405c2f96ae2e37375105881890f7738833b1d62" }, { "version": "bb23c0ab824653be4aa7dfca15b07b3059717004", "status": "affected", "versionType": "git", "lessThan": "43a556b2fd43f2df6dded59c2e26560a27874c24" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.30", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.30" }, { "version": "5.10.267", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.218", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.185", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.154", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.106", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.47", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2.1", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }