CVE-2026-93077: cxl/features: Clamp Get Feature output size to the remaining buffer

CVE-2026-93077: cxl/features: Clamp Get Feature output size to the remaining buffer

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

cxl/features: Clamp Get Feature output size to the remaining buffer

cxl_get_feature() reads a feature in a loop but passes a fixed size_out
as the output capacity every iteration. On the last partial iteration
the buffer has less room left, so a device that returns more than asked
can overflow feat_out.

Use the per-iter size data_to_rd_size, which already tracks the
remaining room, as the output capacity.

The Linux kernel CVE team has assigned CVE-2026-93077 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.15 with commit 5e5ac21f629de796ab5d598b59c5e468c6fe4f95 and fixed in 6.18.52 with commit b8abbd5c2928fd839dab702244cc57b228ab43aa
	Issue introduced in 6.15 with commit 5e5ac21f629de796ab5d598b59c5e468c6fe4f95 and fixed in 7.2.6 with commit ca95b15a0760e7724e61addbdd61050be13b6406
	Issue introduced in 6.15 with commit 5e5ac21f629de796ab5d598b59c5e468c6fe4f95 and fixed in 7.3-rc1 with commit 2aeb21fe557ef154f0cdf4f9745ebd8d5b31ca83

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-2026-93077
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/cxl/core/features.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/b8abbd5c2928fd839dab702244cc57b228ab43aa
	https://git.kernel.org/stable/c/ca95b15a0760e7724e61addbdd61050be13b6406
	https://git.kernel.org/stable/c/2aeb21fe557ef154f0cdf4f9745ebd8d5b31ca83