CVE-2025-39998

Kernel-memory disclosure and panic via oversized names

Published Oct 15, 2025 · Updated Aug 5, 2026

Buffer over-read in the Linux kernel allows local users to disclose kernel stack memory or panic the host through an ALUA configfs read. In target_lu_gp_members_show, snprintf returns the full HBA-and-device-name length after truncating the 256-byte buf, and memcpy uses that oversized value as its source length. An administrator-created HBA and device name pair exceeding 255 characters must already exist; afterward, an unprivileged reader can repeatedly trigger disclosure or a kernel panic without user interaction.

CVSS severity7.1
High
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

Buffer over-read in the Linux kernel allows local users to disclose kernel stack memory or panic the host through an ALUA configfs read. In target_lu_gp_members_show, snprintf returns the full HBA-and-device-name length after truncating the 256-byte buf, and memcpy uses that oversized value as its source length. An administrator-created HBA and device name pair exceeding 255 characters must already exist; afterward, an unprivileged reader can repeatedly trigger disclosure or a kernel panic without user interaction.

The record

CVE
CVE-2025-39998
Published
Oct 15, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-252
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=2.6.38
  2. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <27e06650a5eafe832a90fd2604f0c5e920857fae
  3. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <4b292286949588bd2818e66ff102db278de8dd26
  4. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <53c6351597e6a17ec6619f6f060d54128cb9a187
  5. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <764a91e2fc9639e07aac93bc70e387e6b1e33084
  6. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <a150275831b765b0f1de8b8ff52ec5c6933ac15d
  7. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <ddc79fba132b807ff775467acceaf48b456e008b
  8. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <e6eeee5dc0d9221ff96d1b229b1d0222c8871b84
  9. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <e73fe0eefac3e15bf88fb5b4afae4c76215ee4d4
  10. Affected versionversion=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <f03aa5e39da7d045615b3951d2a6ca1d7132f881

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.38; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <27e06650a5eafe832a90fd2604f0c5e920857fae; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <4b292286949588bd2818e66ff102db278de8dd26; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <53c6351597e6a17ec6619f6f060d54128cb9a187; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <764a91e2fc9639e07aac93bc70e387e6b1e33084; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <a150275831b765b0f1de8b8ff52ec5c6933ac15d; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <ddc79fba132b807ff775467acceaf48b456e008b; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <e6eeee5dc0d9221ff96d1b229b1d0222c8871b84; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <e73fe0eefac3e15bf88fb5b4afae4c76215ee4d4; version=c66ac9db8d4ad9994a02b3e933ea2ccc643e1fe5 <f03aa5e39da7d045615b3951d2a6ca1d7132f881

Published CVSS scores

7.0Oracle LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.1LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/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

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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-252Unchecked Return Value

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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