Linux Kernel up to 6.18-rc1 Terms Of Mailbox API denial of service

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.157/6.6.113/6.12.54/6.17.4/6.18-rc1. It has been declared as critical. The impacted element is an unknown function of the component Terms Of Mailbox API. The manipulation results in denial of service. This vulnerability is identified as CVE-2025-40104. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.1.157/6.6.113/6.12.54/6.17.4/6.18-rc1. Affected is some unknown processing of the component Terms Of Mailbox API. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ixgbevf: fix mailbox API compatibility by negotiating supported features There was backward compatibility in the terms of mailbox API. Various drivers from various OSes supporting 10G adapters from Intel portfolio could easily negotiate mailbox API. This convention has been broken since introducing API 1.4. Commit 0062e7cc955e ("ixgbevf: add VF IPsec offload code") added support for IPSec which is specific only for the kernel ixgbe driver. None of the rest of the Intel 10G PF/VF drivers supports it. And actually lack of support was not included in the IPSec implementation - there were no such code paths. No possibility to negotiate support for the feature was introduced along with introduction of the feature itself. Commit 339f28964147 ("ixgbevf: Add support for new mailbox communication between PF and VF") increasing API version to 1.5 did the same - it introduced code supported specifically by the PF ESX driver. It altered API version for the VF driver in the same time not touching the version defined for the PF ixgbe driver. It led to additional discrepancies, as the code provided within API 1.6 cannot be supported for Linux ixgbe driver as it causes crashes. The issue was noticed some time ago and mitigated by Jake within the commit d0725312adf5 ("ixgbevf: stop attempting IPSEC offload on Mailbox API 1.5"). As a result we have regression for IPsec support and after increasing API to version 1.6 ixgbevf driver stopped to support ESX MBX. To fix this mess add new mailbox op asking PF driver about supported features. Basing on a response determine whether to set support for IPSec and ESX-specific enhanced mailbox. New mailbox op, for compatibility purposes, must be added within new API revision, as API version of OOT PF & VF drivers is already increased to 1.6 and doesn't incorporate features negotiate op. Features negotiation mechanism gives possibility to be extended with new features when needed in the future.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2025-40104 since 04/16/2025. The technical details are unknown and an exploit is not available.

The vulnerability scanner Nessus provides a plugin with the ID 272053 (Linux Distros Unpatched Vulnerability : CVE-2025-40104), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.158, 6.6.114, 6.12.55, 6.17.5 or 6.18-rc2 eliminates this vulnerability. Applying the patch 871ac1cd4ce4804defcb428cbb003fd84c415ff4/2e0aab9ddaf1428602c78f12064cd1e6ffcc4d18/bf580112ed61736c2645a893413a04732505d4b1/a376e29b1b196dc90b50df7e5e3947e3026300c4/a7075f501bd33c93570af759b6f4302ef0175168 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (272053) and CERT Bund (WID-SEC-2025-2450). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • Dell NetWorker

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 272053
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-40104

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.158/6.6.114/6.12.55/6.17.5/6.18-rc2
Patch: 871ac1cd4ce4804defcb428cbb003fd84c415ff4/2e0aab9ddaf1428602c78f12064cd1e6ffcc4d18/bf580112ed61736c2645a893413a04732505d4b1/a376e29b1b196dc90b50df7e5e3947e3026300c4/a7075f501bd33c93570af759b6f4302ef0175168

Timelineinfo

04/16/2025 CVE reserved
10/30/2025 +197 days Advisory disclosed
10/30/2025 +0 days VulDB entry created
02/16/2026 +108 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40104 (🔒)
GCVE (CVE): GCVE-0-2025-40104
GCVE (VulDB): GCVE-100-330546
CERT Bund: WID-SEC-2025-2450 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/30/2025 14:06
Updated: 02/16/2026 00:06
Changes: 10/30/2025 14:06 (58), 10/31/2025 06:13 (7), 11/01/2025 13:04 (2), 12/21/2025 23:48 (1), 02/16/2026 00:06 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you know our Splunk app?

Download it now for free!