CVE-2025-39825

File disclosure and corruption via SMB rename race

Published Sep 16, 2025 · Updated Sep 16, 2025

A race condition in affected Linux kernels' SMB client allows local users to access the wrong file and interrupt directory operations. During cifs_rename2, the target dentry remains hashed while deferred closes and outstanding I/O are processed, so a concurrent open can escape deleted-handle marking. An unprivileged local user needs ordinary directory access on an already-mounted CIFS share; winning the race enables stale-handle reads or writes, target-file deletion, or directory starvation.

CVSS severity7.8
High
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in affected Linux kernels' SMB client allows local users to access the wrong file and interrupt directory operations. During cifs_rename2, the target dentry remains hashed while deferred closes and outstanding I/O are processed, so a concurrent open can escape deleted-handle marking. An unprivileged local user needs ordinary directory access on an already-mounted CIFS share; winning the race enables stale-handle reads or writes, target-file deletion, or directory starvation.

The record

CVE
CVE-2025-39825
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362, T1485, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <24b9ed739c8c5b464d983e12cf308982f3ae93c2
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <289f945acb20b9b54fe4d13895e44aa58965ddb2
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9991af5e09924f6f3b3e6996a5e09f9504b4358
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9e7de284da0be5b44dbe79d71573f9f7f9b144c
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d84291fc7453df7881a970716f8256273aca5747

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <24b9ed739c8c5b464d983e12cf308982f3ae93c2; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <289f945acb20b9b54fe4d13895e44aa58965ddb2; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9991af5e09924f6f3b3e6996a5e09f9504b4358; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9e7de284da0be5b44dbe79d71573f9f7f9b144c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d84291fc7453df7881a970716f8256273aca5747

Published CVSS scores

4.7NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1485Data Destruction
T1005Data from Local System

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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