Linux Kernel up to 6.1.177/6.12.96/6.18.39/7.1.4 Bluetooth EIR net/bluetooth/eir.c eir_create_adv_data adv_data/adv_data_len out-of-bounds write

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.8	$0-$5k	2.07

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.177/6.12.96/6.18.39/7.1.4 and classified as very critical. This issue affects the function eir_create_adv_data of the file net/bluetooth/eir.c of the component Bluetooth EIR. Such manipulation of the argument adv_data/adv_data_len leads to out-of-bounds write. This vulnerability is listed as CVE-2026-64539. The attack must be carried out locally. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 6.1.177/6.12.96/6.18.39/7.1.4. Affected by this issue is the function eir_create_adv_data of the file net/bluetooth/eir.c of the component Bluetooth EIR. The manipulation of the argument adv_data/adv_data_len with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-64539 since 07/19/2026. The exploitation is known to be easy. Local access is required to approach this attack. Additional levels of successful authentication are necessary for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 07/27/2026).

Upgrading to version 6.1.178, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch 0f0b6232af56441d0a2dcb173cc4f8d8aab39014/09301f1fdf2aef8cce34d0c4650c30e7edb1ced9/f1b4df9c260c51726da2e86e19322825fddeefd0/57077eeb586c42f124bc09e018449362223067b3/6f5fb689fdf80bdd143f22a502f9eb1f3c85e286 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.177
• 6.12.0
• 6.12.1
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• 6.12.96
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
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• 6.18.37
• 6.18.38
• 6.18.39
• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 7.8

VulDB Base Score: 8.2
VulDB Temp Score: 7.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.178/6.12.97/6.18.40/7.1.5/7.2-rc1
Patch: 0f0b6232af56441d0a2dcb173cc4f8d8aab39014/09301f1fdf2aef8cce34d0c4650c30e7edb1ced9/f1b4df9c260c51726da2e86e19322825fddeefd0/57077eeb586c42f124bc09e018449362223067b3/6f5fb689fdf80bdd143f22a502f9eb1f3c85e286

Timelineinfo

07/19/2026 CVE reserved
07/27/2026 +8 days Advisory disclosed
07/27/2026 +0 days VulDB entry created
07/27/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64539 (🔒)
GCVE (CVE): GCVE-0-2026-64539
GCVE (VulDB): GCVE-100-383618

Entryinfo

Created: 07/27/2026 23:38
Changes: 07/27/2026 23:38 (61)
Complete: 🔍
Cache ID: 216::103

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Discussion

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