From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89587: ACPI: pfr_update: fix stack buffer overflow in query_capability()
Date: Fri, 11 Sep 2026 21:44:36 +0200 [thread overview]
Message-ID: <2026091129-CVE-2026-89587-1c31@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
ACPI: pfr_update: fix stack buffer overflow in query_capability()
query_capability() copies four ACPI buffer objects returned by the
firmware _DSM into fixed-size u8[16] fields in struct
pfru_update_cap_info using memcpy with the firmware-supplied length:
memcpy(&cap_hdr->code_type,
elements[CAP_CODE_TYPE_IDX].buffer.pointer,
elements[CAP_CODE_TYPE_IDX].buffer.length);
The same pattern repeats for drv_type, platform_id, and oem_id.
If the firmware returns buffer.length > 16 for any of these fields,
memcpy writes past the destination array.
struct pfru_update_cap_info is stack-allocated in pfru_ioctl().
Confirmed with KASAN on 7.2-rc6: three stack-out-of-bounds reports
are generated when a DSM returns 64-byte buffers, with writes reaching
44 bytes past the end of cap_hdr's [64, 156) frame window into
adjacent stack redzones.
Introduce a helper pointer to out_obj->package.elements and use it
to validate each buffer length against its destination field size
before copying, returning -EINVAL if the firmware supplies an
oversized buffer.
The Linux kernel CVE team has assigned CVE-2026-89587 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.17 with commit 0db89fa243e5edc5de38c88b369e4c3755c5fb74 and fixed in 6.12.109 with commit a2151624b55029dad0ca7efd17fb83a0461c8843
Issue introduced in 5.17 with commit 0db89fa243e5edc5de38c88b369e4c3755c5fb74 and fixed in 6.18.50 with commit 6d4ed2fd022bc862b156e53aae163b61259e1caa
Issue introduced in 5.17 with commit 0db89fa243e5edc5de38c88b369e4c3755c5fb74 and fixed in 7.2.4 with commit 15d2b7f38f95d28652170344f39ee492c55e567c
Issue introduced in 5.17 with commit 0db89fa243e5edc5de38c88b369e4c3755c5fb74 and fixed in 7.3-rc1 with commit ced45be0073a8a31b30b4a7f68cd3a15734515de
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-2026-89587
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/acpi/pfr_update.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/a2151624b55029dad0ca7efd17fb83a0461c8843
https://git.kernel.org/stable/c/6d4ed2fd022bc862b156e53aae163b61259e1caa
https://git.kernel.org/stable/c/15d2b7f38f95d28652170344f39ee492c55e567c
https://git.kernel.org/stable/c/ced45be0073a8a31b30b4a7f68cd3a15734515de
reply other threads:[~2026-09-11 19:59 UTC|newest]
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