Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
CVE-2025-39889
Linux Linux — Bluetooth: l2cap: Check encryption key size on incoming connection
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U N N H 5.5 .0010 0.7 —
AFFECTED
Product Versions Fixed
Linux 4f911a538e089cce808a15dc3277250f4f8daef9 – —
Linux 5.11 – 5.15.181
TIMELINE
Apr 16 Reserved by Linux
Sep 24 Published (CNA: Linux)
Sep 26 RESCORED — CVE-2025-39889 (Linux). CVSS 8.1 → 5.5 (NVD).
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)
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
| April 16, 2025 | Reserved | Reserved by Linux |
| September 24, 2025 | Published | Published (CNA: Linux) |
| September 26, 2026 | RESCORED | RESCORED — CVE-2025-39889 (Linux). CVSS 8.1 → 5.5 (NVD). |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | 4f911a538e089cce808a15dc3277250f4f8daef9 | — |
| Linux | Linux | — | 5.11 | 5.15.181 |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-39889 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.