From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89669: nfsd: initialize copy-notify stateid before publishing it
Date: Fri, 11 Sep 2026 21:45:58 +0200 [thread overview]
Message-ID: <2026091148-CVE-2026-89669-53f8@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
nfsd: initialize copy-notify stateid before publishing it
nfsd4_copy_notify() finished initializing the cpntf state after
nfs4_alloc_init_cpntf_state() had already linked it into the
s2s_cp_stateids IDR and the parent's sc_cp_list, with cs_count == 1 (the
membership reference) and none held for the caller. A racing
OFFLOAD_CANCEL (crafted cl_id == nn->s2s_cp_cl_id plus the guessable
so_id) could reach manage_cpntf_state() and free the entry, turning the
caller's subsequent cpn_cnr_stateid read and cp_p_stateid/cp_p_clid
writes into use-after-free. The owning clientid was also only recorded
after publication, so it could not gate an ownership check in that window.
Record cp_p_stateid and cp_p_clid inside nfs4_alloc_init_cpntf_state()
before nfs4_init_cp_state() publishes the entry, and return it with an
extra reference. The caller reads the stateid under that reference and
drops it with nfs4_put_cpntf_state(); on a late error the laundromat
reaps the entry.
The Linux kernel CVE team has assigned CVE-2026-89669 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 6.12.109 with commit e08a3dcaca0505f861e344a387f37f94d95dbdc2
Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 6.18.50 with commit a4d7fedcaaf33e60a01e53eafca9041ef966212f
Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 7.2.4 with commit 4cdef96892f4fa6e70c405b6e8f2fd6972f3b64b
Issue introduced in 5.6 with commit 624322f1adc58acd0b69f77a6ddc764207e97241 and fixed in 7.3-rc1 with commit 129643893b79f8a3c6b72045f933fbab5ee424ca
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-2026-89669
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/nfsd/nfs4proc.c
fs/nfsd/nfs4state.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/e08a3dcaca0505f861e344a387f37f94d95dbdc2
https://git.kernel.org/stable/c/a4d7fedcaaf33e60a01e53eafca9041ef966212f
https://git.kernel.org/stable/c/4cdef96892f4fa6e70c405b6e8f2fd6972f3b64b
https://git.kernel.org/stable/c/129643893b79f8a3c6b72045f933fbab5ee424ca
reply other threads:[~2026-09-11 20:03 UTC|newest]
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