CVE-2026-64539: Bluetooth: eir: Fix stack OOB write when prepending the Flags AD
CVE-2026-64539 is a vulnerability in Bluetooth: eir: Fix stack OOB write when prepending the Flags AD, rated Moderate by Microsoft, with a CVSS 3.1 base score of 6 (Medium). An attacker can exploit it by an attacker with local access, with high privileges and without user interaction. Microsoft has not reported exploitation in the wild. The EPSS model estimates a 0.13% probability of exploitation activity in the next 30 days, higher than 2% of all scored vulnerabilities. Microsoft released the fix on 10 August 2026, outside Patch Tuesday. It affects 5 products in 1 product family (Open Source Software).
Key facts
- CVE ID
- CVE-2026-64539
- Severity
- Medium CVSS 6
- Microsoft severity
- Moderate
- Exploited in the wild
- No
- Publicly disclosed
- No
- Weakness
- CWE-121
- EPSS
- 0.13% (percentile 2%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- July 2026 Patch Tuesday
- Product families
- Open Source Software
CVSS score and vector
Microsoft scores CVE-2026-64539 at 6 (temporal 6) using CVSS 3.1. Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
| Metric | Value |
|---|---|
| Attack vector | Local |
| Attack complexity | Low |
| Privileges required | High |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | None |
| Integrity impact | High |
| Availability impact | High |
NVD scores it 7.8 (HIGH) with CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products (5)
Open Source Software
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| azl3 kernel 6.6.145.2-1 on Azure Linux 3.0 | ||||
| azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 | ||||
| azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 | Release Notes | Security Update | ||
| azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 | Release Notes | Security Update | ||
| azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 | Release Notes | Security Update | 6.6.161.1-1 |
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 7.8 (HIGH)
- NVD weakness
- CWE-121
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| linux kernel | from 4.1, before 6.1.178 |
| linux kernel | from 6.2, before 6.6.160 |
| linux kernel | from 6.7, before 6.12.97 |
| linux kernel | from 6.13, before 6.18.40 |
| linux kernel | from 6.19, before 7.1.5 |
References
- https://git.kernel.org/stable/c/09301f1fdf2aef8cce34d0c4650c30e7edb1ced9 (Patch)
- https://git.kernel.org/stable/c/0f0b6232af56441d0a2dcb173cc4f8d8aab39014 (Patch)
- https://git.kernel.org/stable/c/57077eeb586c42f124bc09e018449362223067b3 (Patch)
- https://git.kernel.org/stable/c/6f5fb689fdf80bdd143f22a502f9eb1f3c85e286 (Patch)
- https://git.kernel.org/stable/c/9174992ee1045c9c96e53eecda64f49dd7e8fbba (Patch)
- https://git.kernel.org/stable/c/f1b4df9c260c51726da2e86e19322825fddeefd0 (Patch)
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. | |
| 2.0 | Information published. | |
| 3.0 | Information published. | |
| 4.0 | Information published. | |
| 5.0 | Information published. | |
| 6.0 | Information published. | |
| 7.0 | Information published. |