CVE-2026-64539 (GCVE-0-2026-64539)
Vulnerability from cvelistv5 – Published: 2026-07-27 20:10 – Updated: 2026-07-27 20:10
VLAI
EPSS
VEX
Title
Bluetooth: eir: Fix stack OOB write when prepending the Flags AD
Summary
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: eir: Fix stack OOB write when prepending the Flags AD
eir_create_adv_data() builds the advertising data into a fixed-size
buffer ("size", 31 for the legacy path). It may prepend a 3-byte "Flags"
AD structure (LE_AD_NO_BREDR on an LE-only controller) and then copies
the per-instance data without checking that it still fits:
memcpy(ptr, adv->adv_data, adv->adv_data_len);
tlv_data_max_len() only reserves those 3 bytes when the user-supplied
flags carry a managed-flags bit, so an instance added with flags == 0 is
accepted with adv_data_len up to the full buffer. At advertise time the
flags are still prepended, and the memcpy() writes 3 + adv_data_len
bytes into the size-byte buffer:
BUG: KASAN: stack-out-of-bounds in eir_create_adv_data (net/bluetooth/eir.c:301)
Write of size 31 at addr ffff88800a547bdc by task kworker/u9:0/65
Workqueue: hci0 hci_cmd_sync_work
__asan_memcpy (mm/kasan/shadow.c:106)
eir_create_adv_data (net/bluetooth/eir.c:301)
hci_update_adv_data_sync (net/bluetooth/hci_sync.c:1310)
hci_schedule_adv_instance_sync (net/bluetooth/hci_sync.c:1817)
hci_cmd_sync_work (net/bluetooth/hci_sync.c:332)
This frame has 1 object:
[32, 64) 'cp'
The "Flags" structure is added by the kernel, not requested by
userspace, so only prepend it when it fits together with the instance
advertising data; when there is no room for both, drop the flags rather
than the user-provided data.
Reachable by a local user with CAP_NET_ADMIN owning an LE-only
controller on the legacy advertising path.
Severity
No CVSS data available.
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Linux | Linux |
Affected:
b44133ff03be30b55f23036e62f403a3f7784fce , < 0f0b6232af56441d0a2dcb173cc4f8d8aab39014
(git)
Affected: b44133ff03be30b55f23036e62f403a3f7784fce , < 09301f1fdf2aef8cce34d0c4650c30e7edb1ced9 (git) Affected: b44133ff03be30b55f23036e62f403a3f7784fce , < f1b4df9c260c51726da2e86e19322825fddeefd0 (git) Affected: b44133ff03be30b55f23036e62f403a3f7784fce , < 57077eeb586c42f124bc09e018449362223067b3 (git) Affected: b44133ff03be30b55f23036e62f403a3f7784fce , < 6f5fb689fdf80bdd143f22a502f9eb1f3c85e286 (git) |
|
| Linux | Linux |
Affected:
4.1
Unaffected: 0 , < 4.1 (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix) |
{
"containers": {
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"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/bluetooth/eir.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "b44133ff03be30b55f23036e62f403a3f7784fce",
"versionType": "git"
},
{
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"status": "affected",
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{
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{
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{
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"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/bluetooth/eir.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.1"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.178",
"versionStartIncluding": "4.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.97",
"versionStartIncluding": "4.1",
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},
{
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2-rc1",
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: eir: Fix stack OOB write when prepending the Flags AD\n\neir_create_adv_data() builds the advertising data into a fixed-size\nbuffer (\"size\", 31 for the legacy path). It may prepend a 3-byte \"Flags\"\nAD structure (LE_AD_NO_BREDR on an LE-only controller) and then copies\nthe per-instance data without checking that it still fits:\n\n\tmemcpy(ptr, adv-\u003eadv_data, adv-\u003eadv_data_len);\n\ntlv_data_max_len() only reserves those 3 bytes when the user-supplied\nflags carry a managed-flags bit, so an instance added with flags == 0 is\naccepted with adv_data_len up to the full buffer. At advertise time the\nflags are still prepended, and the memcpy() writes 3 + adv_data_len\nbytes into the size-byte buffer:\n\n BUG: KASAN: stack-out-of-bounds in eir_create_adv_data (net/bluetooth/eir.c:301)\n Write of size 31 at addr ffff88800a547bdc by task kworker/u9:0/65\n Workqueue: hci0 hci_cmd_sync_work\n __asan_memcpy (mm/kasan/shadow.c:106)\n eir_create_adv_data (net/bluetooth/eir.c:301)\n hci_update_adv_data_sync (net/bluetooth/hci_sync.c:1310)\n hci_schedule_adv_instance_sync (net/bluetooth/hci_sync.c:1817)\n hci_cmd_sync_work (net/bluetooth/hci_sync.c:332)\n This frame has 1 object:\n [32, 64) \u0027cp\u0027\n\nThe \"Flags\" structure is added by the kernel, not requested by\nuserspace, so only prepend it when it fits together with the instance\nadvertising data; when there is no room for both, drop the flags rather\nthan the user-provided data.\n\nReachable by a local user with CAP_NET_ADMIN owning an LE-only\ncontroller on the legacy advertising path."
}
],
"providerMetadata": {
"dateUpdated": "2026-07-27T20:10:33.363Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/0f0b6232af56441d0a2dcb173cc4f8d8aab39014"
},
{
"url": "https://git.kernel.org/stable/c/09301f1fdf2aef8cce34d0c4650c30e7edb1ced9"
},
{
"url": "https://git.kernel.org/stable/c/f1b4df9c260c51726da2e86e19322825fddeefd0"
},
{
"url": "https://git.kernel.org/stable/c/57077eeb586c42f124bc09e018449362223067b3"
},
{
"url": "https://git.kernel.org/stable/c/6f5fb689fdf80bdd143f22a502f9eb1f3c85e286"
}
],
"title": "Bluetooth: eir: Fix stack OOB write when prepending the Flags AD",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64539",
"datePublished": "2026-07-27T20:10:33.363Z",
"dateReserved": "2026-07-19T15:36:31.795Z",
"dateUpdated": "2026-07-27T20:10:33.363Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2026-64539\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-27T21:17:06.277\",\"lastModified\":\"2026-07-27T21:17:06.277\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nBluetooth: eir: Fix stack OOB write when prepending the Flags AD\\n\\neir_create_adv_data() builds the advertising data into a fixed-size\\nbuffer (\\\"size\\\", 31 for the legacy path). It may prepend a 3-byte \\\"Flags\\\"\\nAD structure (LE_AD_NO_BREDR on an LE-only controller) and then copies\\nthe per-instance data without checking that it still fits:\\n\\n\\tmemcpy(ptr, adv-\u003eadv_data, adv-\u003eadv_data_len);\\n\\ntlv_data_max_len() only reserves those 3 bytes when the user-supplied\\nflags carry a managed-flags bit, so an instance added with flags == 0 is\\naccepted with adv_data_len up to the full buffer. At advertise time the\\nflags are still prepended, and the memcpy() writes 3 + adv_data_len\\nbytes into the size-byte buffer:\\n\\n BUG: KASAN: stack-out-of-bounds in eir_create_adv_data (net/bluetooth/eir.c:301)\\n Write of size 31 at addr ffff88800a547bdc by task kworker/u9:0/65\\n Workqueue: hci0 hci_cmd_sync_work\\n __asan_memcpy (mm/kasan/shadow.c:106)\\n eir_create_adv_data (net/bluetooth/eir.c:301)\\n hci_update_adv_data_sync (net/bluetooth/hci_sync.c:1310)\\n hci_schedule_adv_instance_sync (net/bluetooth/hci_sync.c:1817)\\n hci_cmd_sync_work (net/bluetooth/hci_sync.c:332)\\n This frame has 1 object:\\n [32, 64) \u0027cp\u0027\\n\\nThe \\\"Flags\\\" structure is added by the kernel, not requested by\\nuserspace, so only prepend it when it fits together with the instance\\nadvertising data; when there is no room for both, drop the flags rather\\nthan the user-provided data.\\n\\nReachable by a local user with CAP_NET_ADMIN owning an LE-only\\ncontroller on the legacy advertising path.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/bluetooth/eir.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"b44133ff03be30b55f23036e62f403a3f7784fce\",\"lessThan\":\"0f0b6232af56441d0a2dcb173cc4f8d8aab39014\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b44133ff03be30b55f23036e62f403a3f7784fce\",\"lessThan\":\"09301f1fdf2aef8cce34d0c4650c30e7edb1ced9\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b44133ff03be30b55f23036e62f403a3f7784fce\",\"lessThan\":\"f1b4df9c260c51726da2e86e19322825fddeefd0\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b44133ff03be30b55f23036e62f403a3f7784fce\",\"lessThan\":\"57077eeb586c42f124bc09e018449362223067b3\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b44133ff03be30b55f23036e62f403a3f7784fce\",\"lessThan\":\"6f5fb689fdf80bdd143f22a502f9eb1f3c85e286\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/bluetooth/eir.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.178\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/09301f1fdf2aef8cce34d0c4650c30e7edb1ced9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/0f0b6232af56441d0a2dcb173cc4f8d8aab39014\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/57077eeb586c42f124bc09e018449362223067b3\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6f5fb689fdf80bdd143f22a502f9eb1f3c85e286\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f1b4df9c260c51726da2e86e19322825fddeefd0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
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