CVE-2026-74530 (GCVE-0-2026-74530)
Vulnerability from cvelistv5
Published
2026-08-15 12:27
Modified
2026-08-17 05:48
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback
There is theoretical UAF if the conn is freed while the hci_sync task is
running.
Hold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to
match the previous behavior.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/bluetooth/hci_sync.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "2d91e6244b69d752503b2d44020d8b0e323dbd38",
"status": "affected",
"version": "024421cf39923927ab2b5fe895d1d922b9abe67f",
"versionType": "git"
},
{
"lessThan": "56e78b670356caab0b607e8aad4cf819a1909d07",
"status": "affected",
"version": "024421cf39923927ab2b5fe895d1d922b9abe67f",
"versionType": "git"
},
{
"status": "affected",
"version": "620810ac1f7f1133a9ac403e132b3ad6995ddf39",
"versionType": "git"
},
{
"status": "affected",
"version": "ee0586ad64a805eaf1a9a10100e908627a561e34",
"versionType": "git"
},
{
"lessThan": "6.13",
"status": "affected",
"version": "6.12.28",
"versionType": "semver"
},
{
"lessThan": "6.15",
"status": "affected",
"version": "6.14.6",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/bluetooth/hci_sync.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.15"
},
{
"lessThan": "6.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.8",
"versionStartIncluding": "6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.12.28",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.14.6",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: hold conn in hci_connect_big_sync() callback\n\nThere is theoretical UAF if the conn is freed while the hci_sync task is\nrunning.\n\nHold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to\nmatch the previous behavior."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:A - The bug is in Bluetooth LE ISO BIG Create Sync handling (hci_connect_big_sync), reachable via adjacent BLE traffic that drives HCI events (e.g. HCI_EVT_LE_BIG_INFO_ADV_REPORT through iso_connect_ind) and via local ISO sockets; Bluetooth kernel bugs are scored as Adjacent, not Network.\nAC:L - After 024421cf3992 the path blocks in __hci_cmd_sync_status_sk for up to conn_timeout while only holding a bare hci_conn pointer; an attacker who can open/close an ISO broadcast socket (or race teardown during that wait) controls both sides of the race and can reliably trigger the UAF.\nPR:N - Exploitation does not require root or CAP_NET_ADMIN; adjacent attackers can trigger the vulnerable code through unauthenticated over-the-air BLE broadcasts processed by the kernel HCI layer, and local exploitation only needs standard Bluetooth/ISO socket access available to unprivileged users/apps with Bluetooth permission.\nUI:N - No victim interaction is required beyond attacker-controlled actions such as creating an ISO broadcast listener socket, starting BIG sync, and concurrently closing the socket to free hci_conn while hci_sync work is still running; exploitation does not depend on another user opening files or mounting resources.\nS:U - The use-after-free corrupts kernel heap memory within the Bluetooth/hci_conn subsystem and can lead to local privilege escalation, but it does not cross a VM, IOMMU, or sandbox security boundary into another authority domain.\nC:H - This is a kernel heap use-after-free of struct hci_conn; freed connection objects can be reallocated and read through subsequent dereferences in create_big_complete and hci_le_big_create_sync, providing a standard path to arbitrary kernel memory disclosure.\nI:H - UAF on struct hci_conn allows corrupting connection flags and adjacent heap contents; the structure contains function pointers (cleanup, connect_cfm_cb, disconn_cfm_cb) and is large enough to support heap grooming toward arbitrary write or control-flow hijack.\nA:H - Use-after-free during clear_bit on conn-\u003eflags in create_big_complete, or accessing conn fields after teardown during the blocking BIG sync command, can cause kernel oops/panic and repeated disruption; UAF availability impact is rated High per kernel guidance."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:48:20.035Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/2d91e6244b69d752503b2d44020d8b0e323dbd38"
},
{
"url": "https://git.kernel.org/stable/c/56e78b670356caab0b607e8aad4cf819a1909d07"
}
],
"title": "Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74530",
"datePublished": "2026-08-15T12:27:45.381Z",
"dateReserved": "2026-08-15T05:44:03.912Z",
"dateUpdated": "2026-08-17T05:48:20.035Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…