CVE-2025-38063

Storage I/O stall via throttled preflush requests

Published Jun 18, 2025 · Updated Jul 14, 2026

Improper input validation in the Linux kernel allows local users to stall storage I/O by submitting a preflush request through device mapper. __send_empty_flush() creates a flush bio with REQ_SYNC but without REQ_IDLE, so writeback throttling sends it into wbt_wait and indirectly blocks metadata I/O. Reachability requires low-privilege local access and a device-mapper path; the resulting wait interrupts availability without reported data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in the Linux kernel allows local users to stall storage I/O by submitting a preflush request through device mapper. __send_empty_flush() creates a flush bio with REQ_SYNC but without REQ_IDLE, so writeback throttling sends it into wbt_wait and indirectly blocks metadata I/O. Reachability requires low-privilege local access and a device-mapper path; the resulting wait interrupts availability without reported data disclosure or modification.

The record

CVE
CVE-2025-38063
Published
Jun 18, 2025
Updated
Jul 14, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-20, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record 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=V3.1.5 <*

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
The Linux Kernel Organization · Linuxversion=4.10; version=e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c <2858cda9a8d95e6deee7e3b0a26adde696a9a4f5; version=e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c <52aa28f7b1708d76e315d78b5ed397932a1a97c3; version=e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c <88f7f56d16f568f19e1a695af34a7f4a6ce537a6; version=e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c <95d08924335f3b6f4ea0b92ebfe4fe0731c502d9; version=e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c <b55a97d1bd4083729a60d19beffe85d4c96680de
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*

Published CVSS scores

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.0OracleCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
5.8Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Application or System Exploitation

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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