From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-98449: smb: client: delete compound mids on send failure before unlock
Date: Sun, 18 Oct 2026 17:15:13 +0200 [thread overview]
Message-ID: <2026101808-CVE-2026-98449-c5eb@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
smb: client: delete compound mids on send failure before unlock
When sending a compound request fails, smb_send_rqst() kicks off a
reconnect. compound_send_recv() still has those mids on pending_mid_q,
but it unlocks the server without removing them first.
During reconnect, cifs_abort_connection() walks pending_mid_q and runs
each mid callback. With no response yet, those callbacks return credits
and drop in_flight. Then compound_send_recv()'s send-error path returns
the same credits again. in_flight ends up decremented twice and
smb2_add_credits() WARNs.
syzbot hits this during SMB2_negotiate when the socket send fails.
cifs_call_async() already calls delete_mid() before unlock on send
failure. Do the same for compound chains and set cancelled_mid[] so the
out: path does not delete them again.
The Linux kernel CVE team has assigned CVE-2026-98449 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.0 with commit ee258d79159afed52ca9372aeb9c1a51e89b32ee and fixed in 7.2.9 with commit 70783946f3b5d0c06ec7df0f5e7bec2bfad24efb
Issue introduced in 5.0 with commit ee258d79159afed52ca9372aeb9c1a51e89b32ee and fixed in 7.3-rc5 with commit 8f6f8a48399f82f4a83f7b9f25b9707e0062a4f9
Issue introduced in 4.20.11 with commit 3c57a0be487088b08d9c88998f911eb4a7ba36e4
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-2026-98449
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/client/transport.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/70783946f3b5d0c06ec7df0f5e7bec2bfad24efb
https://git.kernel.org/stable/c/8f6f8a48399f82f4a83f7b9f25b9707e0062a4f9
reply other threads:[~2026-10-18 15:21 UTC|newest]
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