CVE-2025-40301

Bluetooth disruption via unchecked empty skb read

Published Dec 8, 2025 · Updated Aug 5, 2026

Uninitialized memory use in Linux 6.1 and later before applicable stable fixes allows adjacent attackers to disrupt Bluetooth processing. In hci_cmd_complete_evt(), an unknown command opcode can leave the skb empty after hci_event_func() pulls parameters, yet skb->data[0] is read as status. A hostile Bluetooth adapter or compromised controller is required; effects are bounded to one stale byte, command-state corruption, or a Bluetooth stack wedge or hardened-kernel abort.

CVSS severity7.6
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uninitialized memory use in Linux 6.1 and later before applicable stable fixes allows adjacent attackers to disrupt Bluetooth processing. In hci_cmd_complete_evt(), an unknown command opcode can leave the skb empty after hci_event_func() pulls parameters, yet skb->data[0] is read as status. A hostile Bluetooth adapter or compromised controller is required; effects are bounded to one stale byte, command-state corruption, or a Bluetooth stack wedge or hardened-kernel abort.

The record

CVE
CVE-2025-40301
Published
Dec 8, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 8, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.1
  2. Affected versionversion=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <1a0ddaaf97405dbd11d4cb5a961a3f82400e8a50
  3. Affected versionversion=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <5c5f1f64681cc889d9b13e4a61285e9e029d6ab5
  4. Affected versionversion=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <779f83a91d4f1bf5ddfeaf528420cbb6dbf03fa8
  5. Affected versionversion=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <cf2c2acec1cf456c3d11c11a7589e886a0f963a9
  6. Affected versionversion=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <fea895de78d3bb2f0c09db9f10b18f8121b15759

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.1; version=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <1a0ddaaf97405dbd11d4cb5a961a3f82400e8a50; version=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <5c5f1f64681cc889d9b13e4a61285e9e029d6ab5; version=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <779f83a91d4f1bf5ddfeaf528420cbb6dbf03fa8; version=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <cf2c2acec1cf456c3d11c11a7589e886a0f963a9; version=afcb3369f46ed5dc883a7b92f2dd1e264d79d388 <fea895de78d3bb2f0c09db9f10b18f8121b15759

Published CVSS scores

7.6LinuxCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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