Bluetooth: RFCOMM: take rfcomm_mutex for the deferred setup accept
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: take rfcomm_mutex for the deferred setup accept rfcomm_sock_recvmsg() completes a deferred setup by calling rfcomm_dlc_accept() without holding any RFCOMM lock: if (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) { rfcomm_dlc_accept(d); return 0; } and rfcomm_dlc_accept() dereferences the session on its first line: struct sock *sk = d->session->sock->sk; Every other path that touches d->session runs under rfcomm_mutex: rfcomm_dlc_open(), rfcomm_dlc_close(), rfcomm_dlc_exists(), rfcomm_dlc_send_rpn(), and the RFCOMM thread through rfcomm_process_sessions(). rfcomm_connect_ind() is even documented as "called under rfcomm_lock()". This call site is the only one that skips it. The RFCOMM_DEFER_SETUP bit looks like it serialises the accept against teardown, since __rfcomm_dlc_close() returns early when it wins the test_and_clear. But rfcomm_recv_disc() forces the state first: d->state = BT_CLOSED; __rfcomm_dlc_close(d, err); and the early return only covers BT_CONNECT, BT_CONFIG, BT_OPEN and BT_CONNECT2. With the state already BT_CLOSED that switch does not match, the bit is never consulted, and __rfcomm_dlc_close() falls through to rfcomm_dlc_unlink(), which sets d->session = NULL. So a remote DISC on a deferred dlc clears the session while leaving RFCOMM_DEFER_SETUP set. The next recvmsg() then passes the test_and_clear and dereferences a NULL session. No timing window is needed: once the D
CVE-2026-80819
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-80819
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "d8d686dd5662a7c4745e4515f1237a9f3b7df181",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "eb71d5a1ea8ff2683e394b48ae3cd676037ab4c2",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "56f0aa75c7640e46397ef73bea251fcbef9150c0",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "362726c9c6e56eea4262109183e49868c39ccd3a",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "825b95561d7b7c393df9e7bc295451aaeadc3d18",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "d4b1a13b1eff2e80925c7368ffdeaaa50cba93df",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "355bfd57ca4ca881c6eb03ca813b440a094b1f44",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "b405c2f96ae2e37375105881890f7738833b1d62",
"versionType": "git"
},
{
"status": "affected",
"version": "bb23c0ab824653be4aa7dfca15b07b3059717004",
"lessThan": "43a556b2fd43f2df6dded59c2e26560a27874c24",
"versionType": "git"
}
],
"programFiles": [
"net/bluetooth/rfcomm/core.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": "5.10.267",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.218",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.185",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.154",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.106",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.47",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.11",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2.1",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/bluetooth/rfcomm/core.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-80819
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #34836 · Revision 1
- Added to Heist Feed
- Publisher date