Linux Kernel up to 7.2.5 L2CAP l2cap_disconn_ind use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.00

Summaryinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 7.2.5. This vulnerability affects the function l2cap_disconn_ind of the component L2CAP. Such manipulation leads to use after free. This vulnerability is uniquely identified as CVE-2026-90256. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been rated as very critical. Affected by this issue is the function l2cap_disconn_ind of the component L2CAP. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind hci_conn::l2cap_data is accessed without locks in l2cap_disconn_ind via hci_conn_timeout (disc_work) -> hci_proto_disconn_ind -> l2cap_disconn_ind. This is UAF if the l2cap_conn is deleted concurrently. disc_work is disabled sync in hci_conn_del(), so we cannot take hci_dev_lock in disc_work. Fix by using proto_lock to guard l2cap_data, in addition to hdev->lock which is held in other access paths.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-90256 since 09/11/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/17/2026).

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch b495a3a9b33bc4e4613e685bf5c96c136caa22d8/2b66c83ff1751d6bd3201b3017206262ab46dc05 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 7.2.6/7.3-rc1
Patch: b495a3a9b33bc4e4613e685bf5c96c136caa22d8/2b66c83ff1751d6bd3201b3017206262ab46dc05

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90256 (🔒)
GCVE (CVE): GCVE-0-2026-90256
GCVE (VulDB): GCVE-100-406772

Entryinfo

Created: 09/17/2026 21:04
Changes: 09/17/2026 21:04 (59)
Complete: 🔍
Cache ID: 216::103

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