CVE-2024-1638
Bluetooth characteristic LESC security requirement not enforced without additional flags
The documentation specifies that the BT_GATT_PERM_READ_LESC and BT_GATT_PERM_WRITE_LESC defines for a Bluetooth characteristic: Attribute read/write permission with LE Secure Connection encryption. If set, requires that LE Secure Connections is used for read/write access, however this is only true when it is combined with other permissions, namely BT_GATT_PERM_READ_ENCRYPT/BT_GATT_PERM_READ_AUTHEN (for read) or BT_GATT_PERM_WRITE_ENCRYPT/BT_GATT_PERM_WRITE_AUTHEN (for write), if these additional permissions are not set (even in secure connections only mode) then the stack does not perform any permission checks on these characteristics and they can be freely written/read.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Bluetooth characteristic LESC security requirement not enforced without additional flags
The documentation specifies that the BT_GATT_PERM_READ_LESC and BT_GATT_PERM_WRITE_LESC defines for a Bluetooth characteristic: Attribute read/write permission with LE Secure Connection encryption. If set, requires that LE Secure Connections is used for read/write access, however this is only true when it is combined with other permissions, namely BT_GATT_PERM_READ_ENCRYPT/BT_GATT_PERM_READ_AUTHEN (for read) or BT_GATT_PERM_WRITE_ENCRYPT/BT_GATT_PERM_WRITE_AUTHEN (for write), if these additional permissions are not set (even in secure connections only mode) then the stack does not perform any permission checks on these characteristics and they can be freely written/read.
- Record
CVE-2024-1638- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2024-17376
The documentation specifies that the BT_GATT_PERM_READ_LESC and BT_GATT_PERM_WRITE_LESC defines for a Bluetooth characteristic: Attribute read/write permission with LE Secure Connection encryption. If set, requires that LE Secure Connections is used for read/write access, however this is only true when it is combined with other permissions, namely BT_GATT_PERM_READ_ENCRYPT/BT_GATT_PERM_READ_AUTHEN (for read) or BT_GATT_PERM_WRITE_ENCRYPT/BT_GATT_PERM_WRITE_AUTHEN (for write), if these additional permissions are not set (even in secure connections only mode) then the stack does not perform any permission checks on these characteristics and they can be freely written/read.
- Record
EUVD-2024-17376- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Updated
- 2026-11-02
NVD
The documentation specifies that the BT_GATT_PERM_READ_LESC and BT_GATT_PERM_WRITE_LESC defines for a Bluetooth characteristic: Attribute read/write permission with LE Secure Connection encryption. If set, requires that LE Secure Connections is used for read/write access, however this is only true when it is combined with other permissions, namely BT_GATT_PERM_READ_ENCRYPT/BT_GATT_PERM_READ_AUTHEN (for read) or BT_GATT_PERM_WRITE_ENCRYPT/BT_GATT_PERM_WRITE_AUTHEN (for write), if these additional permissions are not set (even in secure connections only mode) then the stack does not perform any permission checks on these characteristics and they can be freely written/read.
- Record
CVE-2024-1638- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
OSV
Bluetooth characteristic LESC security requirement not enforced without additional flags
The documentation specifies that the BT_GATT_PERM_READ_LESC and BT_GATT_PERM_WRITE_LESC defines for a Bluetooth characteristic: Attribute read/write permission with LE Secure Connection encryption. If set, requires that LE Secure Connections is used for read/write access, however this is only true when it is combined with other permissions, namely BT_GATT_PERM_READ_ENCRYPT/BT_GATT_PERM_READ_AUTHEN (for read) or BT_GATT_PERM_WRITE_ENCRYPT/BT_GATT_PERM_WRITE_AUTHEN (for write), if these additional permissions are not set (even in secure connections only mode) then the stack does not perform any permission checks on these characteristics and they can be freely written/read.
- Record
CVE-2024-1638- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-1638 is a high vulnerability (CVSS 8.2) in Zephyrproject Zephyr, published February 19, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.35%, the 29th percentile. No source names a fixed version.