CVE-2025-40048Network attack vector

Guest service hang via interrupt-mask race

Published Oct 28, 2025 · Updated Oct 28, 2025

Race condition in affected Linux kernels allows remote attackers to hang a guest userspace VMBus service through inbound network traffic. The uio_hv_generic callback overwrites the inbound ring interrupt_mask while userspace clears it, allowing a queued message to suppress the only wakeup. The affected gate is a Hyper-V guest using uio_hv_generic for a userspace driver such as DPDK or hv_fcopy; the blocked pread() stops that channel until the application restarts.

CVSS severity7.5
High
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in affected Linux kernels allows remote attackers to hang a guest userspace VMBus service through inbound network traffic. The uio_hv_generic callback overwrites the inbound ring interrupt_mask while userspace clears it, allowing a queued message to suppress the only wakeup. The affected gate is a Hyper-V guest using uio_hv_generic for a userspace driver such as DPDK or hv_fcopy; the blocked pread() stops that channel until the application restarts.

The record

CVE
CVE-2025-40048
Published
Oct 28, 2025
Updated
Oct 28, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=4.10
  2. Affected versionversion=95096f2fbd10186d3e78a328b327afc71428f65f <01ce972e6f9974a7c76943bcb7e93746917db83a
  3. Affected versionversion=95096f2fbd10186d3e78a328b327afc71428f65f <2af39ab5e6dc46b835a52e80a22d0cad430985e3
  4. Affected versionversion=95096f2fbd10186d3e78a328b327afc71428f65f <37bd91f22794dc05436130d6983302cb90ecfe7e
  5. Affected versionversion=95096f2fbd10186d3e78a328b327afc71428f65f <a44f61f878f32071d6378e8dd7c2d47f9490c8f7
  6. Affected versionversion=95096f2fbd10186d3e78a328b327afc71428f65f <b15b7d2a1b09ef5428a8db260251897405a19496
  7. Affected versionversion=95096f2fbd10186d3e78a328b327afc71428f65f <e29587c07537929684faa365027f4b0d87521e1b

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.10; version=95096f2fbd10186d3e78a328b327afc71428f65f <01ce972e6f9974a7c76943bcb7e93746917db83a; version=95096f2fbd10186d3e78a328b327afc71428f65f <2af39ab5e6dc46b835a52e80a22d0cad430985e3; version=95096f2fbd10186d3e78a328b327afc71428f65f <37bd91f22794dc05436130d6983302cb90ecfe7e; version=95096f2fbd10186d3e78a328b327afc71428f65f <a44f61f878f32071d6378e8dd7c2d47f9490c8f7; version=95096f2fbd10186d3e78a328b327afc71428f65f <b15b7d2a1b09ef5428a8db260251897405a19496; version=95096f2fbd10186d3e78a328b327afc71428f65f <e29587c07537929684faa365027f4b0d87521e1b

Published CVSS scores

7.5Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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