CVE-2025-38379Network attack vector

Remote denial of service via uninitialized reconnect work

Published Jul 25, 2025 · Updated Aug 5, 2026

Denial of service in the Linux kernel CIFS client allows remote attackers to panic affected systems via a malicious SMB server. The smb2_reconnect_server function passes a dummy tcon with uninitialized query_interfaces work into smb2_reconnect, which queues invalid delayed work. The target must already have a CIFS share mounted; the trigger emits a kernel warning, panics hosts configured with panic_on_warn, and breaks multichannel interface polling.

CVSS severity7.5
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel CIFS client allows remote attackers to panic affected systems via a malicious SMB server. The smb2_reconnect_server function passes a dummy tcon with uninitialized query_interfaces work into smb2_reconnect, which queues invalid delayed work. The target must already have a CIFS share mounted; the trigger emits a kernel warning, panics hosts configured with panic_on_warn, and breaks multichannel interface polling.

The record

CVE
CVE-2025-38379
Published
Jul 25, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 25, 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=202d7e838967dda02855cd925db7fd8c52c56af7 <0cee638d92ac898d73eccc4e4bab70e9fc95946a
  2. Affected versionversion=2c34f1e095a12be3674fb79d84d1af7896e49245 <3f6932ef25378794894c3c1024092ad14da2d330
  3. Affected versionversion=42ca547b13a20e7cbb04fbdf8d5f089ac4bb35b7 <3bbe46716092d8ef6b0df4b956f585c5cd0fc78e
  4. Affected versionversion=4f81ee0af2b8c4089e308f7cb6b5ea5a4efe5b94 <9d2b629a9dc5c72537645533af1cb11a7d34c4b1
  5. Affected versionversion=6.12.35 <6.12.37
  6. Affected versionversion=6.15.4 <6.15.6
  7. Affected versionversion=6.6.95 <6.6.97

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=202d7e838967dda02855cd925db7fd8c52c56af7 <0cee638d92ac898d73eccc4e4bab70e9fc95946a; version=2c34f1e095a12be3674fb79d84d1af7896e49245 <3f6932ef25378794894c3c1024092ad14da2d330; version=42ca547b13a20e7cbb04fbdf8d5f089ac4bb35b7 <3bbe46716092d8ef6b0df4b956f585c5cd0fc78e; version=4f81ee0af2b8c4089e308f7cb6b5ea5a4efe5b94 <9d2b629a9dc5c72537645533af1cb11a7d34c4b1; version=6.12.35 <6.12.37; version=6.15.4 <6.15.6; version=6.6.95 <6.6.97

Published CVSS scores

5.5Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/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)
Vectornetwork
Privilegesunauthenticated
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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