CVE-2026-98455
En el kernel de Linux se ha resuelto la siguiente vulnerabilidad:
Bluetooth: RFCOMM: corregir la desreferencia de NULL de dlc->session en RFCOMM_CONNINFO
El manejador getsockopt RFCOMM_CONNINFO acepta un socket que no está conectado siempre que la configuración diferida esté habilitada:
El campo dlc->defer_setup se establece en rfcomm_sock_init() cuando rfcomm_connect_ind() crea un socket hijo para una conexión entrante en un socket en escucha que tiene BT_DEFER_SETUP habilitado. Después nunca se borra. Sin embargo, la sesión puede desaparecer por debajo.
rfcomm_recv_disc() fuerza el estado del dlc antes de cerrarlo:
Leer descripción completaMostrar menos
El retorno anticipado RFCOMM_DEFER_SETUP en __rfcomm_dlc_close() solo cubre BT_CONNECT, BT_CONFIG, BT_OPEN y BT_CONNECT2, de modo que, con el estado ya en BT_CLOSED, ese switch no coincide y la función continúa hasta rfcomm_dlc_unlink(), que establece d->session = NULL, mientras que d->defer_setup sigue valiendo 1.
Por tanto, un getsockopt(SOL_RFCOMM, RFCOMM_CONNINFO) sobre el socket aceptado después de ese punto omite la ruta -ENOTCONN (sk->sk_state es BT_CLOSED, pero dlc->defer_setup sigue activo) y desreferencia la sesión NULL. No hace falta ninguna condición de carrera: una vez procesado el DISC, la desreferencia es incondicional.
Se reprodujo en un kernel con KASAN bajo QEMU con un par BR/EDR emulado a través de /dev/vhci: el par levanta un enlace ACL, abre L2CAP en el PSM de RFCOMM, inicia una sesión y envía SABM para un canal vinculado con BT_DEFER_SETUP, y envía DISC para ese dlci después de que el socket haya sido aceptado. Entonces getsockopt(SOL_RFCOMM, RFCOMM_CONNINFO) sobre el socket aceptado provoca:
0x10 es el desplazamiento de sock en struct rfcomm_session; rfcomm_sock_getsockopt_old() está incorporada (inlined) en rfcomm_sock_getsockopt().
El commit 43a556b2fd43 ("Bluetooth: RFCOMM: take rfcomm_mutex for the deferred setup accept") corrigió el mismo problema de "un DISC remoto borra la sesión mientras la configuración diferida sigue marcada" en rfcomm_dlc_accept(); este es el caso restante, en la ruta de getsockopt.
La configuración diferida solo deja un socket utilizable aquí una vez que ha alcanzado BT_CONNECT2, así que se restringe la excepción a ese estado y se comprueba que una sesión esté realmente presente antes de seguirla.
Detalles técnicos trazas, registros y código del informe original
if (sk->sk_state != BT_CONNECTED &&
!rfcomm_pi(sk)->dlc->defer_setup) {
err = -ENOTCONN;
break;
}
l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;
d->state = BT_CLOSED;
__rfcomm_dlc_close(d, err);
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000002: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 1 UID: 0 PID: 150 Comm: init Tainted: G B 7.3.0-rc3-g5dd1818b15d9
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:rfcomm_sock_getsockopt+0x529/0x780
Call Trace:
<TASK>
do_sock_getsockopt+0x3ad/0x7d0
__sys_getsockopt+0x10e/0x1b0
__x64_sys_getsockopt+0xc2/0x160
do_syscall_64+0xda/0x4b0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>Traducción automática del texto original de NVD (en inglés).
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días
- 0.18 %
- Percentil entre todas las CVEs puntuadas
- 7
- Fecha de la puntuación
- 21/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
Mostrar las 8 referencias
- https://git.kernel.org/stable/c/005b23d9e324fe5d0acbcfa70c625f2e81189046
- https://git.kernel.org/stable/c/1c4f7e1177da2f229be04139c27e5370a1cfba52
- https://git.kernel.org/stable/c/46f8ffd0a1f1eb6cbc94946a92c11ef601e228a1
- https://git.kernel.org/stable/c/4bf5ca47203049ce3648f750a53dcdc98bcc9e3e
- https://git.kernel.org/stable/c/84ae3cfd7d3a63591a2eb4faa24faf678c6708aa
- https://git.kernel.org/stable/c/8f5b30cc12c409ff62891e47ed51e6bf0945a3ea
- https://git.kernel.org/stable/c/c3aee3fc1287c8a555baf3895959087cb0c33fe8
- https://git.kernel.org/stable/c/c7362f6a18ed167f52f08ce25eeec8a7818c5004
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-98455",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "c3aee3fc1287c8a555baf3895959087cb0c33fe8",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "4bf5ca47203049ce3648f750a53dcdc98bcc9e3e",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "1c4f7e1177da2f229be04139c27e5370a1cfba52",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "84ae3cfd7d3a63591a2eb4faa24faf678c6708aa",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "c7362f6a18ed167f52f08ce25eeec8a7818c5004",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "8f5b30cc12c409ff62891e47ed51e6bf0945a3ea",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "005b23d9e324fe5d0acbcfa70c625f2e81189046",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "46f8ffd0a1f1eb6cbc94946a92c11ef601e228a1",
"versionType": "git"
}
],
"programFiles": [
"net/bluetooth/rfcomm/sock.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.30"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.30",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.271",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/bluetooth/rfcomm/sock.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:16:55.863",
"references": [
{
"url": "https://git.kernel.org/stable/c/005b23d9e324fe5d0acbcfa70c625f2e81189046",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/1c4f7e1177da2f229be04139c27e5370a1cfba52",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/46f8ffd0a1f1eb6cbc94946a92c11ef601e228a1",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/4bf5ca47203049ce3648f750a53dcdc98bcc9e3e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/84ae3cfd7d3a63591a2eb4faa24faf678c6708aa",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/8f5b30cc12c409ff62891e47ed51e6bf0945a3ea",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c3aee3fc1287c8a555baf3895959087cb0c33fe8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c7362f6a18ed167f52f08ce25eeec8a7818c5004",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"lastModified": "2026-10-19T10:18:54.803",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}