CVE-2025-40308

Local service interruption via unregistered BCSP receive

Published Dec 8, 2025 · Updated May 23, 2026

NULL pointer dereference in the Linux kernel Bluetooth BCSP driver allows local users to trigger a kernel fault through crafted TTY input. The bcsp_recv function processes received bytes without first verifying the HCI_UART_REGISTERED flag, then dereferences uninitialized protocol state. Local access to a TTY routed into an unregistered BCSP discipline is required; the resulting oops can panic or reboot hosts configured to panic on oops.

CVSS severityUnavailable
Unscored
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux kernel Bluetooth BCSP driver allows local users to trigger a kernel fault through crafted TTY input. The bcsp_recv function processes received bytes without first verifying the HCI_UART_REGISTERED flag, then dereferences uninitialized protocol state. Local access to a TTY routed into an unregistered BCSP discipline is required; the resulting oops can panic or reboot hosts configured to panic on oops.

The record

CVE
CVE-2025-40308
Published
Dec 8, 2025
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 8, 2025CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=15543b7bbe7b5f744fdbb44f75b14f81a0117813
  2. Affected versionversion=366ceff495f902182d42b6f41525c2474caf3f9a <55c1519fca830f59a10bbf9aa8209c87b06cf7bc
  3. Affected versionversion=366ceff495f902182d42b6f41525c2474caf3f9a <ca94b2b036c22556c3a66f1b80f490882deef7a6
  4. Affected versionversion=45fa7bd82c6178f4fec0ab94891144a043ec5fe8 <164586725b47f9d61912e6bf17dbaffeff11710b
  5. Affected versionversion=48effdb7a798232db945503cf3f51e0be8070cea <39a7d40314b6288cfa2d13269275e9247a7a055a
  6. Affected versionversion=5.10.237 <5.10.247
  7. Affected versionversion=5.15.181 <5.15.197
  8. Affected versionversion=5.4.293 <5.4.302
  9. Affected versionversion=6.1.135 <6.1.159
  10. Affected versionversion=6.12.24 <6.12.58
  11. Affected versionversion=6.13.12 <6.14
  12. Affected versionversion=6.14.3 <6.15
  13. Affected versionversion=6.15
  14. Affected versionversion=6.6.88 <6.6.117
  15. Affected versionversion=6b7a32fa9bacdebd98c18b2a56994116995ee643 <b420a4c7f915fc1c94ad1f6ca740acc046d94334
  16. Affected versionversion=806464634e7fc6b523160defeeddb1ade2a72f81 <799cd62cbcc3f12ee04b33ef390ff7d41c37d671
  17. Affected versionversion=9cf7dccaa7f4c56d2089700e5cb11f85a8d5f6cf <8b892dbef3887dbe9afdc7176d1a5fd90e1636aa
  18. Affected versionversion=a4b89a45b12b69bc82c8137346b150a118e02c26
  19. Affected versionversion=d71a57a34ab6bbc95dc461158403c02e8ff3f912 <b65ca9708bfbf47d8b7bd44b7c574bd16798e9c9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=15543b7bbe7b5f744fdbb44f75b14f81a0117813; version=366ceff495f902182d42b6f41525c2474caf3f9a <55c1519fca830f59a10bbf9aa8209c87b06cf7bc; version=366ceff495f902182d42b6f41525c2474caf3f9a <ca94b2b036c22556c3a66f1b80f490882deef7a6; version=45fa7bd82c6178f4fec0ab94891144a043ec5fe8 <164586725b47f9d61912e6bf17dbaffeff11710b; version=48effdb7a798232db945503cf3f51e0be8070cea <39a7d40314b6288cfa2d13269275e9247a7a055a; version=5.10.237 <5.10.247; version=5.15.181 <5.15.197; version=5.4.293 <5.4.302; version=6.1.135 <6.1.159; version=6.12.24 <6.12.58; version=6.13.12 <6.14; version=6.14.3 <6.15; version=6.15; version=6.6.88 <6.6.117; version=6b7a32fa9bacdebd98c18b2a56994116995ee643 <b420a4c7f915fc1c94ad1f6ca740acc046d94334; version=806464634e7fc6b523160defeeddb1ade2a72f81 <799cd62cbcc3f12ee04b33ef390ff7d41c37d671; version=9cf7dccaa7f4c56d2089700e5cb11f85a8d5f6cf <8b892dbef3887dbe9afdc7176d1a5fd90e1636aa; version=a4b89a45b12b69bc82c8137346b150a118e02c26; version=d71a57a34ab6bbc95dc461158403c02e8ff3f912 <b65ca9708bfbf47d8b7bd44b7c574bd16798e9c9

Published CVSS scores

No CVSS assessment is available in this record.

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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