CVE-2025-37776Network attack vector

Kernel code execution via oplock use-after-free

Published May 1, 2025 · Updated Aug 5, 2026

Use-after-free in the ksmbd SMB server in Linux allows remote authenticated users to crash the host or execute code in the kernel. smb_break_all_levII_oplock() drops its RCU read lock during list traversal, allowing concurrent handle cleanup to free an oplock_info object before later dereferences. A running ksmbd server and a completed SMB session with share access are required; exploitation can panic the host or execute attacker-controlled kernel code.

CVSS severity8.8
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the ksmbd SMB server in Linux allows remote authenticated users to crash the host or execute code in the kernel. smb_break_all_levII_oplock() drops its RCU read lock during list traversal, allowing concurrent handle cleanup to free an oplock_info object before later dereferences. A running ksmbd server and a completed SMB session with share access are required; exploitation can panic the host or execute attacker-controlled kernel code.

The record

CVE
CVE-2025-37776
Published
May 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 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=0626e6641f6b467447c81dd7678a69c66f7746cf <18b4fac5ef17f77fed9417d22210ceafd6525fc7
  2. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <296cb5457cc6f4a754c4ae29855f8a253d52bcc6
  3. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <d54ab1520d43e95f9b2e22d7a05fc9614192e5a5
  4. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <d73686367ad68534257cd88a36ca3c52cb8b81d8
  5. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0626e6641f6b467447c81dd7678a69c66f7746cf <18b4fac5ef17f77fed9417d22210ceafd6525fc7; version=0626e6641f6b467447c81dd7678a69c66f7746cf <296cb5457cc6f4a754c4ae29855f8a253d52bcc6; version=0626e6641f6b467447c81dd7678a69c66f7746cf <d54ab1520d43e95f9b2e22d7a05fc9614192e5a5; version=0626e6641f6b467447c81dd7678a69c66f7746cf <d73686367ad68534257cd88a36ca3c52cb8b81d8; 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

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

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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