CVE-2025-40103

Service interruption via unreleased SMB client references

Published Oct 30, 2025 · Updated Oct 30, 2025

Resource leak in the Linux SMB client allows local users to exhaust kernel resources through repeated CIFS operations. The cifs_do_rename, get_smb2_acl_by_path, and set_smb2_acl paths acquire cifs_sb_tlink references but omit cifs_put_tlink on specific error exits. A local user must exercise affected rename or ACL paths on a CIFS mount; retained references consume memory and can interrupt service.

CVSS severity5.5
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource leak in the Linux SMB client allows local users to exhaust kernel resources through repeated CIFS operations. The cifs_do_rename, get_smb2_acl_by_path, and set_smb2_acl paths acquire cifs_sb_tlink references but omit cifs_put_tlink on specific error exits. A local user must exercise affected rename or ACL paths on a CIFS mount; retained references consume memory and can interrupt service.

The record

CVE
CVE-2025-40103
Published
Oct 30, 2025
Updated
Oct 30, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 30, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 30, 2025Record 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=3.7
  2. Affected versionversion=8ceb984379462f94bdebef3288d569c6e1f912ea <790282abe9d805f08618c1c24ea2529e7259b692
  3. Affected versionversion=8ceb984379462f94bdebef3288d569c6e1f912ea <896bb31e1416f582503db1350cf1bd10dc64e5a6
  4. Affected versionversion=8ceb984379462f94bdebef3288d569c6e1f912ea <c2b77f42205ef485a647f62082c442c1cd69d3fc
  5. Affected versionversion=8ceb984379462f94bdebef3288d569c6e1f912ea <d7dd034c14928306db1b46be277ae439b84dacf9
  6. Affected versionversion=8ceb984379462f94bdebef3288d569c6e1f912ea <e15605b68b490186da2ad8029c0351a9cfb0b9af

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.7; version=8ceb984379462f94bdebef3288d569c6e1f912ea <790282abe9d805f08618c1c24ea2529e7259b692; version=8ceb984379462f94bdebef3288d569c6e1f912ea <896bb31e1416f582503db1350cf1bd10dc64e5a6; version=8ceb984379462f94bdebef3288d569c6e1f912ea <c2b77f42205ef485a647f62082c442c1cd69d3fc; version=8ceb984379462f94bdebef3288d569c6e1f912ea <d7dd034c14928306db1b46be277ae439b84dacf9; version=8ceb984379462f94bdebef3288d569c6e1f912ea <e15605b68b490186da2ad8029c0351a9cfb0b9af

Published CVSS scores

5.5Oracle LinuxCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
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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