CVE-2026-90256

Adjacent kernel compromise via unlocked L2CAP access

Published Sep 17, 2026 · Updated Sep 18, 2026

Use-after-free in Linux Bluetooth L2CAP allows unauthenticated adjacent attackers to crash or compromise the kernel over Bluetooth. l2cap_disconn_ind reads hci_conn::l2cap_data without proto_lock while concurrent l2cap_conn deletion can free the object, leaving disc_reason read through a dangling pointer. Exploitation requires Bluetooth radio range and an enabled, connectable adapter; the race is attacker-driven and retryable without pairing or user interaction.

CVSS severity8.8
High
EPSS probability0.34%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Bluetooth L2CAP allows unauthenticated adjacent attackers to crash or compromise the kernel over Bluetooth. l2cap_disconn_ind reads hci_conn::l2cap_data without proto_lock while concurrent l2cap_conn deletion can free the object, leaving disc_reason read through a dangling pointer. Exploitation requires Bluetooth radio range and an enabled, connectable adapter; the race is attacker-driven and retryable without pairing or user interaction.

The record

CVE
CVE-2026-90256
Published
Sep 17, 2026
Updated
Sep 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 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=18ab6b6078fa8191ca30a3065d57bf35d5635761
  2. Affected versionversion=6.12.20 <6.13
  3. Affected versionversion=6.13.8 <6.14
  4. Affected versionversion=6.14
  5. Affected versionversion=6.6.84 <6.7
  6. Affected versionversion=ab4eedb790cae44313759b50fe47da285e2519d5 <2b66c83ff1751d6bd3201b3017206262ab46dc05
  7. Affected versionversion=ab4eedb790cae44313759b50fe47da285e2519d5 <b495a3a9b33bc4e4613e685bf5c96c136caa22d8
  8. Affected versionversion=efc30877bd4bc85fefe98d80af60fafc86e5775e
  9. Affected versionversion=f87271d21dd4ee83857ca11b94e7b4952749bbae

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=18ab6b6078fa8191ca30a3065d57bf35d5635761; version=6.12.20 <6.13; version=6.13.8 <6.14; version=6.14; version=6.6.84 <6.7; version=ab4eedb790cae44313759b50fe47da285e2519d5 <2b66c83ff1751d6bd3201b3017206262ab46dc05; version=ab4eedb790cae44313759b50fe47da285e2519d5 <b495a3a9b33bc4e4613e685bf5c96c136caa22d8; version=efc30877bd4bc85fefe98d80af60fafc86e5775e; version=f87271d21dd4ee83857ca11b94e7b4952749bbae

Published CVSS scores

8.8Linux CNACVSS:3.1/AV:A/AC:L/PR:N/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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 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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