CVE-2025-38639

Kernel memory disclosure and crash via unterminated name

Published Aug 22, 2025 · Updated Aug 5, 2026

Out-of-bounds read in the Linux kernel xt_nfacct match allows local users to disclose kernel memory or crash the system. The nfacct_mt_checkentry error path passes an attacker-controlled 32-byte account-name field to printk as a string without ensuring a terminating null byte, so formatting reads beyond the field. Reachability requires local low-privileged access and a crafted xt_nfacct rule; the read can copy adjacent heap data into the kernel log or trigger a fatal kernel fault.

CVSS severity7.1
High
EPSS probability0.18%
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 read in the Linux kernel xt_nfacct match allows local users to disclose kernel memory or crash the system. The nfacct_mt_checkentry error path passes an attacker-controlled 32-byte account-name field to printk as a string without ensuring a terminating null byte, so formatting reads beyond the field. Reachability requires local low-privileged access and a crafted xt_nfacct rule; the read can copy adjacent heap data into the kernel log or trigger a fatal kernel fault.

The record

CVE
CVE-2025-38639
Published
Aug 22, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 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=3.3
  2. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <58004aa21e79addaf41667bfe65e93ec51653f18
  3. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <58007fc7b94fb2702000045ff401eb7f5bde7828
  4. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <66d41268ede1e1b6e71ba28be923397ff0b2b9c3
  5. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <7c1ae471da69c09242834e956218ea6a42dd405a
  6. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <b10cfa2de13d28ddd03210eb234422b7ec92725a
  7. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <bf58e667af7d96c8eb9411f926a0a0955f41ce21
  8. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <df13c9c6ce1d55c31d1bd49db65a7fbbd86aab13
  9. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <e021a1eee196887536a6630c5492c23a4c78d452
  10. Affected versionversion=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <e18939176e657a3a20bfbed357b8c55a9f82aba3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.3; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <58004aa21e79addaf41667bfe65e93ec51653f18; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <58007fc7b94fb2702000045ff401eb7f5bde7828; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <66d41268ede1e1b6e71ba28be923397ff0b2b9c3; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <7c1ae471da69c09242834e956218ea6a42dd405a; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <b10cfa2de13d28ddd03210eb234422b7ec92725a; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <bf58e667af7d96c8eb9411f926a0a0955f41ce21; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <df13c9c6ce1d55c31d1bd49db65a7fbbd86aab13; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <e021a1eee196887536a6630c5492c23a4c78d452; version=ceb98d03eac5704820f2ac1f370c9ff385e3a9f5 <e18939176e657a3a20bfbed357b8c55a9f82aba3

Published CVSS scores

7.1Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
5.5NVDCVSS: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 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

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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