CVE-2026-68479: Bluetooth: btrtl: validate firmware patch bounds

From: Greg Kroah-Hartman <[email protected]>

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

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

Bluetooth: btrtl: validate firmware patch bounds

rtlbt_parse_firmware() copies patch_length - 4 bytes before appending the
firmware version. A malformed firmware patch shorter than the version field
can make this subtraction underflow and turn the copy into an oversized
read and write during Bluetooth setup.

The existing patch_offset + patch_length check can also wrap on 32-bit
architectures. Validate the patch length and range without arithmetic
overflow before allocating or copying the patch.

The Linux kernel CVE team has assigned CVE-2026-68479 to this issue.


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

	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 5.10.261 with commit 39e01b4addfbbe177567d6ed1dfb81f9cccb19e6
	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 5.15.212 with commit bda3c598ade6ea03884074b91e31608326684921
	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 6.1.178 with commit a4cb830e0b55ac76c849fd7840afb251f4c028fa
	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 6.6.145 with commit 68c5a2a19987c035eb129e627e579adafb04f637
	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 6.12.97 with commit 83534891c058ed71e251135072640911670869aa
	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 6.18.40 with commit 6744ab60dfac55d1df5733960aad5be300984301
	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 7.1.5 with commit f1ca750c0510bdbb504bf084d2f196ef2af92ea6
	Issue introduced in 4.2 with commit db33c77dddc2ed2cff3061d0b096a9f5ab0c3647 and fixed in 7.2-rc4 with commit 609c5b04a28dc1b0f3af6a7bc93055135b2d2059

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-2026-68479
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/bluetooth/btrtl.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/39e01b4addfbbe177567d6ed1dfb81f9cccb19e6
	https://git.kernel.org/stable/c/bda3c598ade6ea03884074b91e31608326684921
	https://git.kernel.org/stable/c/a4cb830e0b55ac76c849fd7840afb251f4c028fa
	https://git.kernel.org/stable/c/68c5a2a19987c035eb129e627e579adafb04f637
	https://git.kernel.org/stable/c/83534891c058ed71e251135072640911670869aa
	https://git.kernel.org/stable/c/6744ab60dfac55d1df5733960aad5be300984301
	https://git.kernel.org/stable/c/f1ca750c0510bdbb504bf084d2f196ef2af92ea6
	https://git.kernel.org/stable/c/609c5b04a28dc1b0f3af6a7bc93055135b2d2059