From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-68130: ksmbd: defer destroy_previous_session() until after NTLM authentication
Date: Mon, 10 Aug 2026 13:57:27 +0200 [thread overview]
Message-ID: <2026081058-CVE-2026-68130-e575@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: defer destroy_previous_session() until after NTLM authentication
In ntlm_authenticate(), destroy_previous_session() is called using a
user pointer resolved from the client-supplied NTLM blob username field
before the NTLMv2 response is validated. An authenticated attacker can
set the NTLM blob username to match a victim account and set
PreviousSessionId to the victim's session ID; destroy_previous_session()
destroys the victim's session while ksmbd_decode_ntlmssp_auth_blob()
subsequently rejects the request with -EPERM.
Move destroy_previous_session() and the prev_id assignment to after
ksmbd_decode_ntlmssp_auth_blob() returns success and use sess->user
rather than the pre-authentication lookup result. This matches the
ordering already used by krb5_authenticate(), where
destroy_previous_session() is called only after
ksmbd_krb5_authenticate() returns success.
The Linux kernel CVE team has assigned CVE-2026-68130 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.15 with commit e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and fixed in 6.6.148 with commit 5c833074b549e5db125436a6f681af682261f785
Issue introduced in 5.15 with commit e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and fixed in 6.12.101 with commit 243f1614ef2aca2d62a744575f1c24b07cd42757
Issue introduced in 5.15 with commit e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and fixed in 6.18.42 with commit 18705cace0619fd2123737dcd028147774f38181
Issue introduced in 5.15 with commit e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and fixed in 7.1.6 with commit 0ff12308c8a6c16ab68f0a487ffa93d69001dc18
Issue introduced in 5.15 with commit e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and fixed in 7.2-rc5 with commit c74801ee524f477c174a1899782b6c3b6918d407
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-68130
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
fs/smb/server/smb2pdu.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/5c833074b549e5db125436a6f681af682261f785
https://git.kernel.org/stable/c/243f1614ef2aca2d62a744575f1c24b07cd42757
https://git.kernel.org/stable/c/18705cace0619fd2123737dcd028147774f38181
https://git.kernel.org/stable/c/0ff12308c8a6c16ab68f0a487ffa93d69001dc18
https://git.kernel.org/stable/c/c74801ee524f477c174a1899782b6c3b6918d407
reply other threads:[~2026-08-10 12:02 UTC|newest]
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