CVE-2025-40309

Privilege escalation via Bluetooth SCO socket race

Published Dec 8, 2025 · Updated Aug 5, 2026

Use-after-free in the Linux kernel allows local users to escalate privileges through crafted Bluetooth SCO socket activity. An unlocked sk_state check in sco_sock_connect lets concurrent connect and close operations leave conn->sk pointing to a freed socket. Basic local access and Bluetooth link events are sufficient; reclaiming the slot enables kernel-memory disclosure, an eight-byte write, control-flow hijack, or a system crash.

CVSS severity8.0
High
EPSS probability0.24%
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 the Linux kernel allows local users to escalate privileges through crafted Bluetooth SCO socket activity. An unlocked sk_state check in sco_sock_connect lets concurrent connect and close operations leave conn->sk pointing to a freed socket. Basic local access and Bluetooth link events are sufficient; reclaiming the slot enables kernel-memory disclosure, an eight-byte write, control-flow hijack, or a system crash.

The record

CVE
CVE-2025-40309
Published
Dec 8, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 8, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.13
  2. Affected versionversion=e6720779ae612a14ac4ba7fe4fd5b27d900d932c <391f83547b7b2c63e4b572ab838e10a06cfa4425
  3. Affected versionversion=e6720779ae612a14ac4ba7fe4fd5b27d900d932c <ecb9a843be4d6fd710d7026e359f21015a062572

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.13; version=e6720779ae612a14ac4ba7fe4fd5b27d900d932c <391f83547b7b2c63e4b572ab838e10a06cfa4425; version=e6720779ae612a14ac4ba7fe4fd5b27d900d932c <ecb9a843be4d6fd710d7026e359f21015a062572

Published CVSS scores

7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
8.0UbuntuCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.3UbuntuCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.0LinuxCVSS:3.1/AV:A/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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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