CVE-2026-64360: hfs/hfsplus: zero-initialize buffer in hfs_bnode_read

CVE-2026-64360: hfs/hfsplus: zero-initialize buffer in hfs_bnode_read

[Greg Kroah-Hartman]

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

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

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

hfs/hfsplus: zero-initialize buffer in hfs_bnode_read

hfs_bnode_read() can return early without writing to the output buffer
when is_bnode_offset_valid() fails or when check_and_correct_requested_
length() corrects the length to zero.  Callers such as hfs_bnode_read_
u16() and hfs_bnode_read_u8() pass stack-allocated buffers and use the
result unconditionally, leading to KMSAN uninit-value reports.

Rather than initializing at each individual call site, zero the buffer
at the start of hfs_bnode_read() before any validation checks.  This
ensures all callers in both hfs and hfsplus get a deterministic zero
value regardless of which early-return path is taken.

The Linux kernel CVE team has assigned CVE-2026-64360 to this issue.


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

	Issue introduced in 5.10.241 with commit 67ecc81f6492275c9c54280532f558483c99c90e and fixed in 5.10.261 with commit 34684a04777358b2b40ac729e54c8e45359e46b3
	Issue introduced in 5.15.190 with commit a1a60e79502279f996e55052f50cc14919020475 and fixed in 5.15.212 with commit 0b189b2204f1a2612dc68f8d139fb5b80539e710
	Issue introduced in 6.1.149 with commit fe2891a9c43ab87d1a210d61e6438ca6936e2f62 and fixed in 6.1.178 with commit 8f72fd25a57a457866350359ddd27a43caa62c95
	Issue introduced in 6.6.103 with commit 384a66b89f9540a9a8cb0f48807697dfabaece4c and fixed in 6.6.145 with commit 16ca053c2be5f4f3044dccf7fc19237dc820d394
	Issue introduced in 6.12.43 with commit efc095b35b23297e419c2ab4fc1ed1a8f0781a29 and fixed in 6.12.96 with commit d2afc7ecee476f9251dd87444f7fb6a424410922
	Issue introduced in 6.17 with commit a431930c9bac518bf99d6b1da526a7f37ddee8d8 and fixed in 6.18.39 with commit f3461b84a4865d9b5e70fbb71da72ae044a3bcd2
	Issue introduced in 6.17 with commit a431930c9bac518bf99d6b1da526a7f37ddee8d8 and fixed in 7.1.4 with commit d5b45bad75cd2730b8452aed4d3b20a2b2a12576
	Issue introduced in 6.17 with commit a431930c9bac518bf99d6b1da526a7f37ddee8d8 and fixed in 7.2-rc1 with commit d67aadee19ffdf3cc8520c5a4f4d5b2916d30baf
	Issue introduced in 5.4.297 with commit e7d2dc2421e821e4045775e6dc226378328de6f6
	Issue introduced in 6.15.11 with commit fc7f732984ec91f30be3e574e0644066d07f2b78
	Issue introduced in 6.16.2 with commit eec522fd0d28106b14a59ab2d658605febe4a3bb

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-2026-64360
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/hfs/bnode.c
	fs/hfsplus/bnode.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/34684a04777358b2b40ac729e54c8e45359e46b3
	https://git.kernel.org/stable/c/0b189b2204f1a2612dc68f8d139fb5b80539e710
	https://git.kernel.org/stable/c/8f72fd25a57a457866350359ddd27a43caa62c95
	https://git.kernel.org/stable/c/16ca053c2be5f4f3044dccf7fc19237dc820d394
	https://git.kernel.org/stable/c/d2afc7ecee476f9251dd87444f7fb6a424410922
	https://git.kernel.org/stable/c/f3461b84a4865d9b5e70fbb71da72ae044a3bcd2
	https://git.kernel.org/stable/c/d5b45bad75cd2730b8452aed4d3b20a2b2a12576
	https://git.kernel.org/stable/c/d67aadee19ffdf3cc8520c5a4f4d5b2916d30baf