From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-43401: cpufreq: intel_pstate: Fix NULL pointer dereference in update_cpu_qos_request()
Date: Fri, 8 May 2026 16:22:10 +0200 [thread overview]
Message-ID: <2026050840-CVE-2026-43401-c331@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
cpufreq: intel_pstate: Fix NULL pointer dereference in update_cpu_qos_request()
The update_cpu_qos_request() function attempts to initialize the 'freq'
variable by dereferencing 'cpudata' before verifying if the 'policy'
is valid.
This issue occurs on systems booted with the "nosmt" parameter, where
all_cpu_data[cpu] is NULL for the SMT sibling threads. As a result,
any call to update_qos_requests() will result in a NULL pointer
dereference as the code will attempt to access pstate.turbo_freq using
the NULL cpudata pointer.
Also, pstate.turbo_freq may be updated by intel_pstate_get_hwp_cap()
after initializing the 'freq' variable, so it is better to defer the
'freq' until intel_pstate_get_hwp_cap() has been called.
Fix this by deferring the 'freq' assignment until after the policy and
driver_data have been validated.
[ rjw: Added one paragraph to the changelog ]
The Linux kernel CVE team has assigned CVE-2026-43401 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.18 with commit ae1bdd23b99f64335c69d546bff99ca39b894c18 and fixed in 6.18.19 with commit 6bfda7ce56e7d14a677b7bcd6c7a5009cc29aa88
Issue introduced in 6.18 with commit ae1bdd23b99f64335c69d546bff99ca39b894c18 and fixed in 6.19.9 with commit 42738dffb7b0766a45882dff7989401d78f66f92
Issue introduced in 6.18 with commit ae1bdd23b99f64335c69d546bff99ca39b894c18 and fixed in 7.0 with commit ab39cc4cb8ceecdc2b61747433e7237f1ac2b789
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-2026-43401
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:
drivers/cpufreq/intel_pstate.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/6bfda7ce56e7d14a677b7bcd6c7a5009cc29aa88
https://git.kernel.org/stable/c/42738dffb7b0766a45882dff7989401d78f66f92
https://git.kernel.org/stable/c/ab39cc4cb8ceecdc2b61747433e7237f1ac2b789
reply other threads:[~2026-05-08 14:24 UTC|newest]
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