CVE-2025-22039Network attack vector

Authenticated kernel memory disclosure via DACL overflow

Published Apr 16, 2025 · Updated Aug 5, 2026

Out-of-bounds access in Linux ksmbd allows remote authenticated users to disclose kernel memory through crafted SMB2 DACL data. The smb_check_perm_dacl() and smb_inherit_dacl() paths add an attacker-controlled signed dacloffset without overflow checking, letting the sum pass a bounds test before the DACL pointer is dereferenced. Valid share credentials and write access are required; exploitation can expose kernel data, bypass DACL enforcement, corrupt ACL metadata, or crash the kernel.

CVSS severity8.8
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds access in Linux ksmbd allows remote authenticated users to disclose kernel memory through crafted SMB2 DACL data. The smb_check_perm_dacl() and smb_inherit_dacl() paths add an attacker-controlled signed dacloffset without overflow checking, letting the sum pass a bounds test before the DACL pointer is dereferenced. Valid share credentials and write access are required; exploitation can expose kernel data, bypass DACL enforcement, corrupt ACL metadata, or crash the kernel.

The record

CVE
CVE-2025-22039
Published
Apr 16, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 16, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <443b373a4df5a2cb9f7b8c4658b2afedeb16397f
  2. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <6a9cd9ff0fa2bcc30b2bfb8bdb161eb20e44b9dc
  3. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <6b8d379048b168a0dff5ab1acb975b933f368514
  4. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <beff0bc9d69bc8e733f9bca28e2d3df5b3e10e42
  5. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0626e6641f6b467447c81dd7678a69c66f7746cf <443b373a4df5a2cb9f7b8c4658b2afedeb16397f; version=0626e6641f6b467447c81dd7678a69c66f7746cf <6a9cd9ff0fa2bcc30b2bfb8bdb161eb20e44b9dc; version=0626e6641f6b467447c81dd7678a69c66f7746cf <6b8d379048b168a0dff5ab1acb975b933f368514; version=0626e6641f6b467447c81dd7678a69c66f7746cf <beff0bc9d69bc8e733f9bca28e2d3df5b3e10e42; version=5.15

Published CVSS scores

6.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
8.8Linux kernel CNACVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5SUSECVSS: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.

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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo