CVE-2026-99239 - Vulnerability Details

- Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn

Description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn

l2cap_chan may be linked to l2cap_conn at most once. This is assumed in
several places, eg l2cap_chan_del cleanup.

There is a TOCTOU race where the invariant is violated:

[Task 1] [Task 2]
l2cap_chan_connect l2cap_sock_bind
l2cap_chan_lock lock_sock
l2cap_state_change if (sk->sk_state != BT_OPEN)
chan->state = BT_CONNECT
l2cap_sock_state_change_cb chan->state = BT_BOUND
sk->sk_state = BT_BOUND
lock_sock <------------------ release_sock
sk->sk_state = BT_CONNECT

l2cap_sock_connect() does not check sk->sk_state, so since chan->state
is now BT_BOUND, subsequent connect() ends up with second
__l2cap_chan_add.

Explicitly document and check the invariant in __l2cap_chan_add with
WARN_ON_ONCE. The only callsite where it could be hit is
l2cap_chan_connect, so add pre-check there to avoid relying on
chan->state. chan->state read/write is not properly guarded currently so
there can be other TOCTOUC problems.

Add l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write.

Published: 2026-11-02

Score: 7.8 High

EPSS: n/a

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`8f90405a4a6f1f1880dc07996b47bf57c712bd8a`	affected	< 85cc289eb08afa975375f838187369e68b429ee0
`32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b`	affected	< 820579652b24ce277e0097cd65b42bd9b7b8bf07
`8922c7940bae9ce4b1736dddb6362370793835c2`	affected	< e618d928ec7f88cbeadfa3542adcac40f474e629
`91047a4396a8b1857a6f712a90cf33ec0012b189`	affected	< fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2
`0b0e2bf39cf99e458d991b9df253727e036a7d7d`	affected	< 52fe88e4ef87311eee32b45c65603e7c69e75e7d
`d3b739db5dc6f688a60d56da872fabaf65246032`	affected	< 10c705dd706aa93164ba41f2566f15206d6c178e
`b66774b48dd98f07254951f74ea6f513efe7ff8b`	affected	< 73820561d8cbfd3364a29b8fa77f1707f26029da
`b66774b48dd98f07254951f74ea6f513efe7ff8b`	affected	< d3afd7803f9bc2a8c4270199497b60158b2fc647
`50c38d9f42a529691e4e67ea9cedf4f0bfc8d277`	affected	—
`5.10.265`	affected	< 5.10.273
`5.15.216`	affected	< 5.15.224
`6.1.183`	affected	< 6.1.191
`6.6.145`	affected	< 6.6.161
`6.12.97`	affected	< 6.12.115
`6.18.39`	affected	< 6.18.60
`7.1.4`	affected	< 7.2

Linux

affected

Version	Status	Constraints
`7.2`	affected	—
`0`	unaffected	< 7.2
`5.10.273`	unaffected	≤ 5.10.*
`5.15.224`	unaffected	≤ 5.15.*
`6.1.191`	unaffected	≤ 6.1.*
`6.6.161`	unaffected	≤ 6.6.*
`6.12.115`	unaffected	≤ 6.12.*
`6.18.60`	unaffected	≤ 6.18.*
`7.2.14`	unaffected	≤ 7.2.*
`7.3.1`	unaffected	≤ 7.3.*

No data.

Vendor Product Confidence Versions

Linux

100%

Version	Status	Scheme	Platform
`[8f90405a4a6f1f1880dc07996b47bf57c712bd8a,85cc289eb08afa975375f838187369e68b429ee0)`	affected	code_commit	—
`[32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b,820579652b24ce277e0097cd65b42bd9b7b8bf07)`	affected	code_commit	—
`[8922c7940bae9ce4b1736dddb6362370793835c2,e618d928ec7f88cbeadfa3542adcac40f474e629)`	affected	code_commit	—
`[91047a4396a8b1857a6f712a90cf33ec0012b189,fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2)`	affected	code_commit	—
`[0b0e2bf39cf99e458d991b9df253727e036a7d7d,52fe88e4ef87311eee32b45c65603e7c69e75e7d)`	affected	code_commit	—
`[d3b739db5dc6f688a60d56da872fabaf65246032,10c705dd706aa93164ba41f2566f15206d6c178e)`	affected	code_commit	—
`[b66774b48dd98f07254951f74ea6f513efe7ff8b,73820561d8cbfd3364a29b8fa77f1707f26029da)`	affected	code_commit	—
`[b66774b48dd98f07254951f74ea6f513efe7ff8b,d3afd7803f9bc2a8c4270199497b60158b2fc647)`	affected	code_commit	—
`50c38d9f42a529691e4e67ea9cedf4f0bfc8d277`	affected	code_commit	—
`[5.10.265,5.10.273)`	affected	semver	—
`[5.15.216,5.15.224)`	affected	semver	—
`[6.1.183,6.1.191)`	affected	semver	—
`[6.6.145,6.6.161)`	affected	semver	—
`[6.12.97,6.12.115)`	affected	semver	—
`[6.18.39,6.18.60)`	affected	semver	—
`[7.1.4,7.2)`	affected	generic	—

Linux

100%

Version	Status	Scheme	Platform
`7.2`	affected	generic	—
`[0,7.2)`	unaffected	generic	—
`[5.10.273,5.11.0)`	unaffected	semver	—
`[5.15.224,5.16.0)`	unaffected	semver	—
`[6.1.191,6.2.0)`	unaffected	semver	—
`[6.6.161,6.7.0)`	unaffected	semver	—
`[7.2.14,7.3.0)`	unaffected	semver	—
`[7.3.1,7.4.0)`	unaffected	semver	—

Linux

Linux Kernel

100%

Version	Status	Scheme	Platform
`[8f90405a4a6f1f1880dc07996b47bf57c712bd8a,85cc289eb08afa975375f838187369e68b429ee0)`	affected	code_commit	—
`[32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b,820579652b24ce277e0097cd65b42bd9b7b8bf07)`	affected	code_commit	—
`[8922c7940bae9ce4b1736dddb6362370793835c2,e618d928ec7f88cbeadfa3542adcac40f474e629)`	affected	code_commit	—
`[91047a4396a8b1857a6f712a90cf33ec0012b189,fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2)`	affected	code_commit	—
`[0b0e2bf39cf99e458d991b9df253727e036a7d7d,52fe88e4ef87311eee32b45c65603e7c69e75e7d)`	affected	code_commit	—
`[d3b739db5dc6f688a60d56da872fabaf65246032,10c705dd706aa93164ba41f2566f15206d6c178e)`	affected	code_commit	—
`[b66774b48dd98f07254951f74ea6f513efe7ff8b,73820561d8cbfd3364a29b8fa77f1707f26029da)`	affected	code_commit	—
`[b66774b48dd98f07254951f74ea6f513efe7ff8b,d3afd7803f9bc2a8c4270199497b60158b2fc647)`	affected	code_commit	—
`50c38d9f42a529691e4e67ea9cedf4f0bfc8d277`	affected	code_commit	—
`[5.10.265,5.10.273)`	affected	semver	—
`[5.15.216,5.15.224)`	affected	semver	—
`[6.1.183,6.1.191)`	affected	semver	—
`[6.6.145,6.6.161)`	affected	semver	—
`[6.12.97,6.12.115)`	affected	semver	—
`[6.18.39,6.18.60)`	affected	semver	—
`[7.1.4,7.2)`	affected	generic	—

Linux

Linux Kernel

100%

Version	Status	Scheme	Platform
`7.2`	affected	generic	—
`[0,7.2)`	unaffected	generic	—
`[5.10.273,5.11.0)`	unaffected	semver	—
`[5.15.224,5.16.0)`	unaffected	semver	—
`[6.1.191,6.2.0)`	unaffected	semver	—
`[6.6.161,6.7.0)`	unaffected	semver	—
`[7.2.14,7.3.0)`	unaffected	semver	—
`[7.3.1,7.4.0)`	unaffected	semver	—

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Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/10c705dd706aa93164ba41f2566f15206d6c178e
https://git.kernel.org/stable/c/52fe88e4ef87311eee32b45c65603e7c69e75e7d
https://git.kernel.org/stable/c/73820561d8cbfd3364a29b8fa77f1707f26029da
https://git.kernel.org/stable/c/820579652b24ce277e0097cd65b42bd9b7b8bf07
https://git.kernel.org/stable/c/85cc289eb08afa975375f838187369e68b429ee0
https://git.kernel.org/stable/c/d3afd7803f9bc2a8c4270199497b60158b2fc647
https://git.kernel.org/stable/c/e618d928ec7f88cbeadfa3542adcac40f474e629
https://git.kernel.org/stable/c/fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2

History

Mon, 02 Nov 2026 19:15:00 +0000

Type	Values Removed	Values Added
First Time appeared		Linux linux
Vendors & Products		Linux linux

Mon, 02 Nov 2026 18:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-362

Mon, 02 Nov 2026 16:15:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn l2cap_chan may be linked to l2cap_conn at most once. This is assumed in several places, eg l2cap_chan_del cleanup. There is a TOCTOU race where the invariant is violated: [Task 1] [Task 2] l2cap_chan_connect l2cap_sock_bind l2cap_chan_lock lock_sock l2cap_state_change if (sk->sk_state != BT_OPEN) chan->state = BT_CONNECT l2cap_sock_state_change_cb chan->state = BT_BOUND sk->sk_state = BT_BOUND lock_sock <------------------ release_sock sk->sk_state = BT_CONNECT l2cap_sock_connect() does not check sk->sk_state, so since chan->state is now BT_BOUND, subsequent connect() ends up with second __l2cap_chan_add. Explicitly document and check the invariant in __l2cap_chan_add with WARN_ON_ONCE. The only callsite where it could be hit is l2cap_chan_connect, so add pre-check there to avoid relying on chan->state. chan->state read/write is not properly guarded currently so there can be other TOCTOUC problems. Add l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write.
Title		Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/10c705dd706aa93164ba41f2566f15206d6c178e https://git.kernel.org/stable/c/52fe88e4ef87311eee32b45c65603e7c69e75e7d https://git.kernel.org/stable/c/73820561d8cbfd3364a29b8fa77f1707f26029da https://git.kernel.org/stable/c/820579652b24ce277e0097cd65b42bd9b7b8bf07 https://git.kernel.org/stable/c/85cc289eb08afa975375f838187369e68b429ee0 https://git.kernel.org/stable/c/d3afd7803f9bc2a8c4270199497b60158b2fc647 https://git.kernel.org/stable/c/e618d928ec7f88cbeadfa3542adcac40f474e629 https://git.kernel.org/stable/c/fabaff1c59ff2cc89cb7e5bd0186a5e15f0c73b2
Metrics		cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}`

Subscriptions

Linux Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-11-02T16:06:43.262Z

Updated: 2026-11-02T16:06:43.262Z

Reserved: 2026-09-25T10:25:14.403Z

Link: CVE-2026-99239

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-11-02T16:17:49.540

Modified: 2026-11-02T16:17:49.540

Link: CVE-2026-99239

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-11-02T19:00:06Z

Weaknesses

CWE-362

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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