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CVE-2026-31476

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CVE-2026-31476

Published: Apr 22, 2026

Modified: Jun 1, 2026

PUBLISHED

CVSS v3.1

8.2

HIGH

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: do not expire session on binding failure When a multichannel session binding request fails (e.g. wrong password), the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED. However, during binding, sess points to the target session looked up via ksmbd_session_lookup_slowpath() -- which belongs to another connection's user. This allows a remote attacker to invalidate any active session by simply sending a binding request with a wrong password (DoS). Fix this by skipping session expiration when the failed request was a binding attempt, since the session does not belong to the current connection. The reference taken by ksmbd_session_lookup_slowpath() is still correctly released via ksmbd_user_session_put().

VendorProductVersions

Linux

Linux

affected
f5a544e3bab78142207e0242d22442db85ba1eff - < 4642ea35c03cf3d3558c009df4757cdb7af3f82d
affected
f5a544e3bab78142207e0242d22442db85ba1eff - < f5300690c23c5ac860499bb37dbc09cf43fd62e6
affected
f5a544e3bab78142207e0242d22442db85ba1eff - < 6fafc4c4238e538969f1375f9ecdc6587c53f1cc
affected
f5a544e3bab78142207e0242d22442db85ba1eff - < 1d1888b4a7aec518b707f6eca0bf08992c0e8da3
affected
f5a544e3bab78142207e0242d22442db85ba1eff - < a897064a457056acb976e20e3007cdf553de340f

+2 more versions

Linux

Linux

affected
5.15
unaffected
0 - < 5.15
unaffected
5.15.209 - <= 5.15.*
unaffected
6.1.168 - <= 6.1.*
unaffected
6.6.131 - <= 6.6.*

+4 more versions

CVSS v3.1 Details

CVSS v3.1 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

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