CVE-2025-37947Public exploitNetwork attack vector

Kernel memory corruption via unchecked stream offset

Published May 20, 2025 · Updated Aug 5, 2026

Out-of-bounds write in Linux kernel ksmbd allows remote authenticated users to corrupt kernel memory via crafted SMB stream writes. ksmbd_vfs_stream_write truncates the allocation to XATTR_SIZE_MAX but memcpy uses the attacker-controlled offset and adjusted count without validating the existing stream length. Reachability requires an authenticated account, a writable share, and streams_xattr; the published exploit achieves local root, while remote code execution also needs an information leak.

CVSS severity8.8
High
EPSS probability0.55%
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 write in Linux kernel ksmbd allows remote authenticated users to corrupt kernel memory via crafted SMB stream writes. ksmbd_vfs_stream_write truncates the allocation to XATTR_SIZE_MAX but memcpy uses the attacker-controlled offset and adjusted count without validating the existing stream length. Reachability requires an authenticated account, a writable share, and streams_xattr; the published exploit achieves local root, while remote code execution also needs an information leak.

The record

CVE
CVE-2025-37947
Published
May 20, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 20, 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 <04c8a38c60346bb5a7c49b276de7233f703ce9cb
  2. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <0ca6df4f40cf4c32487944aaf48319cb6c25accc
  3. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <7f61da79df86fd140c7768e668ad846bfa7ec8e1
  4. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <d62ba16563a86aae052f96d270b3b6f78fca154c
  5. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <e6356499fd216ed6343ae0363f4c9303f02c5034
  6. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0626e6641f6b467447c81dd7678a69c66f7746cf <04c8a38c60346bb5a7c49b276de7233f703ce9cb; version=0626e6641f6b467447c81dd7678a69c66f7746cf <0ca6df4f40cf4c32487944aaf48319cb6c25accc; version=0626e6641f6b467447c81dd7678a69c66f7746cf <7f61da79df86fd140c7768e668ad846bfa7ec8e1; version=0626e6641f6b467447c81dd7678a69c66f7746cf <d62ba16563a86aae052f96d270b3b6f78fca154c; version=0626e6641f6b467447c81dd7678a69c66f7746cf <e6356499fd216ed6343ae0363f4c9303f02c5034; version=5.15

Published CVSS scores

8.8LinuxCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8UbuntuCVSS: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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

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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