CVE-2025-37844

Kernel crash via unchecked CIFS debug context

Published May 9, 2025 · Updated May 23, 2026

NULL pointer dereference in the Linux CIFS client allows local users to crash the kernel during cancelled SMB2 close handling. In smb2_handle_cancelled_close(), an absent tcon->ses leaves server NULL, but cifs_server_dbg() dereferences it outside the session check. Exploitation requires local low-privileged access and a closing CIFS tree connection without an attached session; the consequence is availability loss.

CVSS severity5.5
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux CIFS client allows local users to crash the kernel during cancelled SMB2 close handling. In smb2_handle_cancelled_close(), an absent tcon->ses leaves server NULL, but cifs_server_dbg() dereferences it outside the session check. Exploitation requires local low-privileged access and a closing CIFS tree connection without an attached session; the consequence is availability loss.

The record

CVE
CVE-2025-37844
Published
May 9, 2025
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 9, 2025CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=53e83828d352304fec5e19751f38ed8c65e6ec2f
  2. Affected versionversion=5.6.7 <5.7
  3. Affected versionversion=5.7
  4. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <20048e658652e731f5cadf4a695925e570ca0ff9
  5. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <6c14ee6af8f1f188b668afd6d003f7516a507b08
  6. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <864ba5c651b03830f36f0906c21af05b15c1aaa6
  7. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <9c9000cb91b986eb7f75835340c67857ab97c09b
  8. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <b2a1833e1c63e2585867ebeaf4dd41494dcede4b
  9. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <b4885bd5935bb26f0a414ad55679a372e53f9b9b
  10. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <ba3ce6c60cd5db258687dfeba9fc608f5e7cadf3
  11. Affected versionversion=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <e0717385f5c51e290c2cd2ad4699a778316b5132

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=53e83828d352304fec5e19751f38ed8c65e6ec2f; version=5.6.7 <5.7; version=5.7; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <20048e658652e731f5cadf4a695925e570ca0ff9; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <6c14ee6af8f1f188b668afd6d003f7516a507b08; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <864ba5c651b03830f36f0906c21af05b15c1aaa6; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <9c9000cb91b986eb7f75835340c67857ab97c09b; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <b2a1833e1c63e2585867ebeaf4dd41494dcede4b; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <b4885bd5935bb26f0a414ad55679a372e53f9b9b; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <ba3ce6c60cd5db258687dfeba9fc608f5e7cadf3; version=e79b0332ae06b4895dcecddf4bbc5d3917e9383c <e0717385f5c51e290c2cd2ad4699a778316b5132

Published CVSS scores

5.5NIST NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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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