CVE-2025-39788

Service interruption via oversized Exynos UFS shift

Published Sep 11, 2025 · Updated May 12, 2026

Improper input validation in the Linux Exynos UFS driver allows local users to interrupt service on affected Linux and SIMATIC systems. A 32-bit integer expression shifts by 32 when generating the UTP request-slot mask, causing undefined behavior and writing zero to HCI_UTRL_NEXUS_TYPE. The faulty path requires an Exynos UFS host with 32 transfer-request slots, including Google gs101; no remote trigger is reported.

CVSS severity5.5
Medium
EPSS probability0.17%
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 Exynos UFS driver allows local users to interrupt service on affected Linux and SIMATIC systems. A 32-bit integer expression shifts by 32 when generating the UTP request-slot mask, causing undefined behavior and writing zero to HCI_UTRL_NEXUS_TYPE. The faulty path requires an Exynos UFS host with 32 transfer-request slots, including Google gs101; no remote trigger is reported.

The record

CVE
CVE-2025-39788
Published
Sep 11, 2025
Updated
May 12, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, CWE-20
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 2025CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=55f4b1f73631a0817717fe6e98517de51b4c3527 <01510a9e8222f11cce064410f3c2fcf0756c0a08
  2. Affected versionversion=55f4b1f73631a0817717fe6e98517de51b4c3527 <01aad16c2257ab8ff33b152b972c9f2e1af47912
  3. Affected versionversion=55f4b1f73631a0817717fe6e98517de51b4c3527 <098b2c8ee208c77126839047b9e6e1925bb35baa
  4. Affected versionversion=55f4b1f73631a0817717fe6e98517de51b4c3527 <5b9f1ef293428ea9c0871d96fcec2a87c4445832
  5. Affected versionversion=55f4b1f73631a0817717fe6e98517de51b4c3527 <6d53b2a134da77eb7fe65c5c7c7a3c193539a78a
  6. Affected versionversion=55f4b1f73631a0817717fe6e98517de51b4c3527 <c1f025da8f370a015e412b55cbcc583f91de8316
  7. Affected versionversion=55f4b1f73631a0817717fe6e98517de51b4c3527 <dc8fb963742f1a38d284946638f9358bdaa0ddee
  8. Affected versionversion=5.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=55f4b1f73631a0817717fe6e98517de51b4c3527 <01510a9e8222f11cce064410f3c2fcf0756c0a08; version=55f4b1f73631a0817717fe6e98517de51b4c3527 <01aad16c2257ab8ff33b152b972c9f2e1af47912; version=55f4b1f73631a0817717fe6e98517de51b4c3527 <098b2c8ee208c77126839047b9e6e1925bb35baa; version=55f4b1f73631a0817717fe6e98517de51b4c3527 <5b9f1ef293428ea9c0871d96fcec2a87c4445832; version=55f4b1f73631a0817717fe6e98517de51b4c3527 <6d53b2a134da77eb7fe65c5c7c7a3c193539a78a; version=55f4b1f73631a0817717fe6e98517de51b4c3527 <c1f025da8f370a015e412b55cbcc583f91de8316; version=55f4b1f73631a0817717fe6e98517de51b4c3527 <dc8fb963742f1a38d284946638f9358bdaa0ddee; version=5.9
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/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 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

CWE-787Out-of-bounds Write
CWE-20Improper Input Validation

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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