CVE-2025-39889

HIGH

Linux Kernel - Inadequate Encryption Key Size Validation in Bluetooth L2CAP

Title source: llm
STIX 2.1

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: l2cap: Check encryption key size on incoming connection This is required for passing GAP/SEC/SEM/BI-04-C PTS test case: Security Mode 4 Level 4, Responder - Invalid Encryption Key Size - 128 bit This tests the security key with size from 1 to 15 bytes while the Security Mode 4 Level 4 requests 16 bytes key size. Currently PTS fails with the following logs: - expected:Connection Response: Code: [3 (0x03)] Code Identifier: (lt)WildCard: Exists(gt) Length: [8 (0x0008)] Destination CID: (lt)WildCard: Exists(gt) Source CID: [64 (0x0040)] Result: [3 (0x0003)] Connection refused - Security block Status: (lt)WildCard: Exists(gt), but received:Connection Response: Code: [3 (0x03)] Code Identifier: [1 (0x01)] Length: [8 (0x0008)] Destination CID: [64 (0x0040)] Source CID: [64 (0x0040)] Result: [0 (0x0000)] Connection Successful Status: [0 (0x0000)] No further information available And HCI logs: < HCI Command: Read Encrypti.. (0x05|0x0008) plen 2 Handle: 14 Address: 00:1B:DC:F2:24:10 (Vencer Co., Ltd.) > HCI Event: Command Complete (0x0e) plen 7 Read Encryption Key Size (0x05|0x0008) ncmd 1 Status: Success (0x00) Handle: 14 Address: 00:1B:DC:F2:24:10 (Vencer Co., Ltd.) Key size: 7 > ACL Data RX: Handle 14 flags 0x02 dlen 12 L2CAP: Connection Request (0x02) ident 1 len 4 PSM: 4097 (0x1001) Source CID: 64 < ACL Data TX: Handle 14 flags 0x00 dlen 16 L2CAP: Connection Response (0x03) ident 1 len 8 Destination CID: 64 Source CID: 64 Result: Connection successful (0x0000) Status: No further information available (0x0000)

Scores

CVSS v3 8.1
EPSS 0.0001
EPSS Percentile 0.5%
Attack Vector ADJACENT_NETWORK
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-326
Status published
Products (22)
linux/Kernel 5.11.0 - 5.15.181linux
linux/Kernel 5.16.0 - 6.1.135linux
linux/Kernel 6.13.0 - 6.14.4linux
linux/Kernel 6.2.0 - 6.6.88linux
linux/Kernel 6.7.0 - 6.12.25linux
Linux/Linux < 5.11
Linux/Linux 288c06973daae4637f25a0d1bdaf65fdbf8455f9 - 24b2cdfc16e9bd6ab3d03b8e01c590755bd3141f
Linux/Linux 288c06973daae4637f25a0d1bdaf65fdbf8455f9 - 522e9ed157e3c21b4dd623c79967f72c21e45b78
Linux/Linux 288c06973daae4637f25a0d1bdaf65fdbf8455f9 - 9e3114958d87ea88383cbbf38c89e04b8ea1bce5
Linux/Linux 288c06973daae4637f25a0d1bdaf65fdbf8455f9 - c6d527bbd3d3896375079f5dbc8b7f96734a3ba5
... and 12 more
Published Sep 24, 2025
Tracked Since Feb 18, 2026