CVE-2025-39975Network attack vector

Kernel-data disclosure and crashes via response misindexing

Published Oct 15, 2025 · Updated Oct 15, 2025

Out-of-bounds access in the Linux SMB client allows remote attackers controlling an SMB server to expose kernel data or crash clients. smb2_compound_op() indexes command statuses and response buffers with mismatched loop indices, so a failed QUERY_WSL_EA response can drive memcpy() past its allocation. The client must access an already mounted attacker-controlled or compromised SMB share; ordinary path lookup then exposes heap data, corrupts inode metadata, or triggers a kernel oops.

CVSS severity9.8
Critical
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in the Linux SMB client allows remote attackers controlling an SMB server to expose kernel data or crash clients. smb2_compound_op() indexes command statuses and response buffers with mismatched loop indices, so a failed QUERY_WSL_EA response can drive memcpy() past its allocation. The client must access an already mounted attacker-controlled or compromised SMB share; ordinary path lookup then exposes heap data, corrupts inode metadata, or triggers a kernel oops.

The record

CVE
CVE-2025-39975
Published
Oct 15, 2025
Updated
Oct 15, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 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=3681c74d342db75b0d641ba60de27bf73e16e66b <093615fc76063ea08d454ba86677ce64c736e806
  2. Affected versionversion=3681c74d342db75b0d641ba60de27bf73e16e66b <fbe2dc6a9c7318f7263f5e4d50f6272b931c5756
  3. Affected versionversion=5ddcc9e92d54548219985ce4de88618fb53e14ec <ba7bcfd52c66dd1c2dfa5142aca7e4a70b62dfa5
  4. Affected versionversion=6.14
  5. Affected versionversion=77aefd1d9b790f60634adebbdcfffbe934f41c34
  6. Affected versionversion=efe8db3ecaa40a8520dc9a54283dcecd82ceea9c <bfb1e2aad1fecef8320fd71332acde0d53a8d699

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3681c74d342db75b0d641ba60de27bf73e16e66b <093615fc76063ea08d454ba86677ce64c736e806; version=3681c74d342db75b0d641ba60de27bf73e16e66b <fbe2dc6a9c7318f7263f5e4d50f6272b931c5756; version=5ddcc9e92d54548219985ce4de88618fb53e14ec <ba7bcfd52c66dd1c2dfa5142aca7e4a70b62dfa5; version=6.14; version=77aefd1d9b790f60634adebbdcfffbe934f41c34; version=efe8db3ecaa40a8520dc9a54283dcecd82ceea9c <bfb1e2aad1fecef8320fd71332acde0d53a8d699

Published CVSS scores

9.8LinuxCVSS:3.1/AV:N/AC:L/PR:N/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.

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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

No sourced classifications are available.

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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