Linux Kernel up to 6.18.39 Bluetooth sco_conn_ready sk use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k1.33+

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.15.211/6.1.177/6.6.144/6.12.96/6.18.39. It has been classified as very critical. The affected element is the function sco_conn_ready of the component Bluetooth. Performing a manipulation of the argument sk results in use after free. This vulnerability was named CVE-2026-89774. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 5.15.211/6.1.177/6.6.144/6.12.96/6.18.39. This affects the function sco_conn_ready of the component Bluetooth. The manipulation of the argument sk with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: SCO: hold sk properly in sco_conn_ready sk deref in sco_conn_ready must be done either under conn->lock, or holding a refcount, to avoid concurrent close. conn->sk and parent sk is currently accessed without either, and without checking parent->sk_state: [Task 1] [Task 2] sco_sock_release sco_conn_ready sk = conn->sk lock_sock(sk) conn->sk = NULL lock_sock(sk) release_sock(sk) sco_sock_kill(sk) UAF on sk deref and similarly for access to sco_get_sock_listen() return value. Fix possible UAF by holding sk refcount in sco_conn_ready() and making sco_get_sock_listen() increase refcount. Also recheck after lock_sock that the socket is still valid. Adjust conn->sk locking so it's protected also by lock_sock() of the associated socket if any.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-89774 since 09/11/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/16/2026).

Upgrading to version 5.15.212, 6.1.178, 6.6.145, 6.12.97 or 6.18.40 eliminates this vulnerability. Applying the patch 50aae396dc30377bec8e3b181b8346f8fd38f7d8/6e3840578aaad1a296aab1eaaa89ea3b7d5cbae1/d141d9b769bcd1b747898528c5023270cda040f2/73cb063f5ec6ca51eb1e246c6d332563002ac277/7199c78c3a3e399a4dc439d845826793880ccedc/4e37f6452d586b95c346a9abdd2fb80b67794f39 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-80255). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
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 5.15.212/6.1.178/6.6.145/6.12.97/6.18.40
Patch: 50aae396dc30377bec8e3b181b8346f8fd38f7d8/6e3840578aaad1a296aab1eaaa89ea3b7d5cbae1/d141d9b769bcd1b747898528c5023270cda040f2/73cb063f5ec6ca51eb1e246c6d332563002ac277/7199c78c3a3e399a4dc439d845826793880ccedc/4e37f6452d586b95c346a9abdd2fb80b67794f39

Timelineinfo

09/11/2026 CVE reserved
09/16/2026 +5 days Advisory disclosed
09/16/2026 +0 days VulDB entry created
09/16/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-89774 (🔒)
GCVE (CVE): GCVE-0-2026-89774
GCVE (VulDB): GCVE-100-405543
EUVD: 🔒

Entryinfo

Created: 09/16/2026 10:44
Updated: 09/16/2026 11:27
Changes: 09/16/2026 10:44 (60), 09/16/2026 11:27 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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