CVE-2025-21936

Kernel crash via unchecked Bluetooth message allocation

Published Apr 1, 2025 · Updated May 11, 2026

NULL pointer dereference in Linux Bluetooth management allows local users to crash the kernel during device-connection reporting. mgmt_device_connected() fails to check whether mgmt_alloc_skb() returned NULL before passing the pointer to skb_put(). Reaching the fault requires local low-privilege access and an allocation failure while a Bluetooth connection event is built; the reported consequence is a system crash only.

CVSS severity5.5
Medium
EPSS probability0.20%
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 Linux Bluetooth management allows local users to crash the kernel during device-connection reporting. mgmt_device_connected() fails to check whether mgmt_alloc_skb() returned NULL before passing the pointer to skb_put(). Reaching the fault requires local low-privilege access and an allocation failure while a Bluetooth connection event is built; the reported consequence is a system crash only.

The record

CVE
CVE-2025-21936
Published
Apr 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=5.17
  2. Affected versionversion=e96741437ef0a5d18144e790ac894397efda0924 <7841180342c9a0fd97d54f3e62c7369309b5cd84
  3. Affected versionversion=e96741437ef0a5d18144e790ac894397efda0924 <7d39387886ffe220323cbed5c155233c3276926b
  4. Affected versionversion=e96741437ef0a5d18144e790ac894397efda0924 <bdb1805c248e9694dbb3ffa8867cef2e52cf7261
  5. Affected versionversion=e96741437ef0a5d18144e790ac894397efda0924 <d8df010f72b8a32aaea393e36121738bb53ed905
  6. Affected versionversion=e96741437ef0a5d18144e790ac894397efda0924 <dc516e66fb28c61b248b393e2ddd63bd7f104969

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.17; version=e96741437ef0a5d18144e790ac894397efda0924 <7841180342c9a0fd97d54f3e62c7369309b5cd84; version=e96741437ef0a5d18144e790ac894397efda0924 <7d39387886ffe220323cbed5c155233c3276926b; version=e96741437ef0a5d18144e790ac894397efda0924 <bdb1805c248e9694dbb3ffa8867cef2e52cf7261; version=e96741437ef0a5d18144e790ac894397efda0924 <d8df010f72b8a32aaea393e36121738bb53ed905; version=e96741437ef0a5d18144e790ac894397efda0924 <dc516e66fb28c61b248b393e2ddd63bd7f104969

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 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

CWE-476NULL Pointer Dereference

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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