CVE-2025-21969

System crash via L2CAP connection lifetime race

Published Apr 1, 2025 · Updated Aug 5, 2026

Use-after-free in affected Linux kernel Bluetooth L2CAP releases from 5.17.14 allows physically proximate attackers to crash the system. The hci command-sync path frees l2cap_conn while queued hci_rx_work can still pass it to l2cap_send_cmd because access lacks the device lock that synchronizes teardown. A Bluetooth peer that wins this race can repeatedly dereference freed slab memory and trigger a kernel panic, interrupting the host.

CVSS severity7.8
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in affected Linux kernel Bluetooth L2CAP releases from 5.17.14 allows physically proximate attackers to crash the system. The hci command-sync path frees l2cap_conn while queued hci_rx_work can still pass it to l2cap_send_cmd because access lacks the device lock that synchronizes teardown. A Bluetooth peer that wins this race can repeatedly dereference freed slab memory and trigger a kernel panic, interrupting the host.

The record

CVE
CVE-2025-21969
Published
Apr 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1499.004
Attack vector
adjacent
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 1, 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=5.17.14 <5.18
  2. Affected versionversion=5.18
  3. Affected versionversion=995c917d6818b39308ac6baf3f6573cb0486a238
  4. Affected versionversion=9b3628d79b46f06157affc56fdb218fdd4988321 <7790a79c6fce8d5d552bc64f5c82819f719e4f28
  5. Affected versionversion=9b3628d79b46f06157affc56fdb218fdd4988321 <b4f82f9ed43aefa79bec2504ae8c29be0c0f5d1d
  6. Affected versionversion=9b3628d79b46f06157affc56fdb218fdd4988321 <c96cce853542b3b13da3738f35ef1be8cfcc9d1d
  7. Affected versionversion=9b3628d79b46f06157affc56fdb218fdd4988321 <f8094625a591eeb0b75b1bd9e713fac1d93f5ca9

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.17.14 <5.18; version=5.18; version=995c917d6818b39308ac6baf3f6573cb0486a238; version=9b3628d79b46f06157affc56fdb218fdd4988321 <7790a79c6fce8d5d552bc64f5c82819f719e4f28; version=9b3628d79b46f06157affc56fdb218fdd4988321 <b4f82f9ed43aefa79bec2504ae8c29be0c0f5d1d; version=9b3628d79b46f06157affc56fdb218fdd4988321 <c96cce853542b3b13da3738f35ef1be8cfcc9d1d; version=9b3628d79b46f06157affc56fdb218fdd4988321 <f8094625a591eeb0b75b1bd9e713fac1d93f5ca9

Published CVSS scores

7.8CISA ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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)
Vectoradjacent
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application or System Exploitation

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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