Bluetooth: l2cap: Check encryption key size on incoming connection

Summary

CVECVE-2025-39889
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-09-24 11:15:32 UTC
Updated2026-04-02 09:16:19 UTC
DescriptionIn 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)

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-326 | CWE-326 CWE-326 Inadequate Encryption Strength


VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1ADPDECLARED5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.1HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED8.1HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 4f911a538e089cce808a15dc3277250f4f8daef9 ed503d340a501e414114ddc614a3aae4f6e9eae2 git Not specified
CNA Linux Linux affected 288c06973daae4637f25a0d1bdaf65fdbf8455f9 24b2cdfc16e9bd6ab3d03b8e01c590755bd3141f git Not specified
CNA Linux Linux affected 288c06973daae4637f25a0d1bdaf65fdbf8455f9 c6d527bbd3d3896375079f5dbc8b7f96734a3ba5 git Not specified
CNA Linux Linux affected 288c06973daae4637f25a0d1bdaf65fdbf8455f9 9e3114958d87ea88383cbbf38c89e04b8ea1bce5 git Not specified
CNA Linux Linux affected 288c06973daae4637f25a0d1bdaf65fdbf8455f9 d49798ecd26e0ee7995a7fc1e90ca5cd9b4402d6 git Not specified
CNA Linux Linux affected 288c06973daae4637f25a0d1bdaf65fdbf8455f9 d4ca2fd218caafbf50e3343ba1260c6a23b5676a git Not specified
CNA Linux Linux affected 288c06973daae4637f25a0d1bdaf65fdbf8455f9 522e9ed157e3c21b4dd623c79967f72c21e45b78 git Not specified
CNA Linux Linux affected 5.11 Not specified
CNA Linux Linux unaffected 5.11 semver Not specified
CNA Linux Linux unaffected 5.15.181 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.135 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.88 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.25 6.12.* semver Not specified
CNA Linux Linux unaffected 6.14.4 6.14.* semver Not specified
CNA Linux Linux unaffected 6.15 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/9e3114958d87ea88383cbbf38c89e04b8ea1bce5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/c6d527bbd3d3896375079f5dbc8b7f96734a3ba5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/d49798ecd26e0ee7995a7fc1e90ca5cd9b4402d6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/522e9ed157e3c21b4dd623c79967f72c21e45b78 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/ed503d340a501e414114ddc614a3aae4f6e9eae2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d4ca2fd218caafbf50e3343ba1260c6a23b5676a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/24b2cdfc16e9bd6ab3d03b8e01c590755bd3141f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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