CVE-2025-40123

Kernel data exposure and corruption via BPF tailcalls

Published Nov 12, 2025 · Updated Aug 5, 2026

Type confusion in the Linux kernel BPF subsystem allows local users with BPF loading access to read or corrupt kernel data. The tail-call map compatibility check compares only program type and omits expected_attach_type, allowing a program validated for one BPF context to run against another and dereference an uninitialized xdp_buff txq pointer. Exploitation requires local BPF program-loading access; a crafted tail call can disclose or modify kernel data or repeatedly trigger a kernel crash.

CVSS severity7.8
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Type confusion in the Linux kernel BPF subsystem allows local users with BPF loading access to read or corrupt kernel data. The tail-call map compatibility check compares only program type and omits expected_attach_type, allowing a program validated for one BPF context to run against another and dereference an uninitialized xdp_buff txq pointer. Exploitation requires local BPF program-loading access; a crafted tail call can disclose or modify kernel data or repeatedly trigger a kernel crash.

The record

CVE
CVE-2025-40123
Published
Nov 12, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 12, 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=4.17
  2. Affected versionversion=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <08cb3dc9d2b44f153d0bcf2cb966e4a94b5d0f32
  3. Affected versionversion=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <4540aed51b12bc13364149bf95f6ecef013197c0
  4. Affected versionversion=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <a99de19128aec0913f3d529f529fbbff5edfaff8
  5. Affected versionversion=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <c1ad19b5d8e23123503dcaf2d4342e1b90b923ad
  6. Affected versionversion=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <f856c598080ba7ce1252867b8ecd6ad5bdaf9a6a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.17; version=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <08cb3dc9d2b44f153d0bcf2cb966e4a94b5d0f32; version=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <4540aed51b12bc13364149bf95f6ecef013197c0; version=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <a99de19128aec0913f3d529f529fbbff5edfaff8; version=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <c1ad19b5d8e23123503dcaf2d4342e1b90b923ad; version=5e43f899b03a3492ce5fc44e8900becb04dae9c0 <f856c598080ba7ce1252867b8ecd6ad5bdaf9a6a

Published CVSS scores

7.8Linux Kernel CVE TeamCVSS:3.1/AV:L/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)
Vectorlocal
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo