Linux Kernel up to 6.17.2 pread race condition

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.
4.4$0-$5k0.00

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 5.15.194/6.1.155/6.6.111/6.12.52/6.17.2. This vulnerability affects the function pread. The manipulation leads to race condition. This vulnerability is referenced as CVE-2025-40048. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.15.194/6.1.155/6.6.111/6.12.52/6.17.2. It has been rated as critical. This issue affects the function pread. The manipulation with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: uio_hv_generic: Let userspace take care of interrupt mask Remove the logic to set interrupt mask by default in uio_hv_generic driver as the interrupt mask value is supposed to be controlled completely by the user space. If the mask bit gets changed by the driver, concurrently with user mode operating on the ring, the mask bit may be set when it is supposed to be clear, and the user-mode driver will miss an interrupt which will cause a hang. For eg- when the driver sets inbound ring buffer interrupt mask to 1, the host does not interrupt the guest on the UIO VMBus channel. However, setting the mask does not prevent the host from putting a message in the inbound ring buffer. So let’s assume that happens, the host puts a message into the ring buffer but does not interrupt. Subsequently, the user space code in the guest sets the inbound ring buffer interrupt mask to 0, saying “Hey, I’m ready for interrupts”. User space code then calls pread() to wait for an interrupt. Then one of two things happens: * The host never sends another message. So the pread() waits forever. * The host does send another message. But because there’s already a message in the ring buffer, it doesn’t generate an interrupt. This is the correct behavior, because the host should only send an interrupt when the inbound ring buffer transitions from empty to not-empty. Adding an additional message to a ring buffer that is not empty is not supposed to generate an interrupt on the guest. Since the guest is waiting in pread() and not removing messages from the ring buffer, the pread() waits forever. This could be easily reproduced in hv_fcopy_uio_daemon if we delay setting interrupt mask to 0. Similarly if hv_uio_channel_cb() sets the interrupt_mask to 1, there’s a race condition. Once user space empties the inbound ring buffer, but before user space sets interrupt_mask to 0, the host could put another message in the ring buffer but it wouldn’t interrupt. Then the next pread() would hang. Fix these by removing all instances where interrupt_mask is changed, while keeping the one in set_event() unchanged to enable userspace control the interrupt mask by writing 0/1 to /dev/uioX.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2025-40048 since 04/16/2025. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 271874 (Linux Distros Unpatched Vulnerability : CVE-2025-40048), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.195, 6.1.156, 6.6.112, 6.12.53, 6.17.3 or 6.18-rc1 eliminates this vulnerability. Applying the patch a44f61f878f32071d6378e8dd7c2d47f9490c8f7/01ce972e6f9974a7c76943bcb7e93746917db83a/2af39ab5e6dc46b835a52e80a22d0cad430985e3/37bd91f22794dc05436130d6983302cb90ecfe7e/e29587c07537929684faa365027f4b0d87521e1b/b15b7d2a1b09ef5428a8db260251897405a19496 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 (271874) and CERT Bund (WID-SEC-2025-2431). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

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

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.6
VulDB Meta Temp Score: 4.4

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

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

Exploitinginfo

Class: Race condition
CWE: CWE-362
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: 271874
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-40048

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.15.195/6.1.156/6.6.112/6.12.53/6.17.3/6.18-rc1
Patch: a44f61f878f32071d6378e8dd7c2d47f9490c8f7/01ce972e6f9974a7c76943bcb7e93746917db83a/2af39ab5e6dc46b835a52e80a22d0cad430985e3/37bd91f22794dc05436130d6983302cb90ecfe7e/e29587c07537929684faa365027f4b0d87521e1b/b15b7d2a1b09ef5428a8db260251897405a19496

Timelineinfo

04/16/2025 CVE reserved
10/28/2025 +195 days Advisory disclosed
10/28/2025 +0 days VulDB entry created
05/20/2026 +203 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40048 (🔒)
GCVE (CVE): GCVE-0-2025-40048
GCVE (VulDB): GCVE-100-330245
CERT Bund: WID-SEC-2025-2431 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/28/2025 14:34
Updated: 05/20/2026 01:45
Changes: 10/28/2025 14:34 (58), 10/30/2025 05:37 (7), 10/30/2025 13:58 (2), 10/31/2025 09:59 (1), 11/24/2025 15:14 (1), 12/22/2025 00:54 (1), 02/08/2026 16:45 (1), 02/15/2026 19:08 (1), 05/20/2026 01:45 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you know our Splunk app?

Download it now for free!