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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-25 · updated 2026-09-04
Weakness: CWE-908

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.

Affected products

Linux kernel: from 5.4.297 before 5.5; from 5.10.241 before 5.10.261; from 5.15.190 before 5.15.212; from 6.1.149 before 6.1.178; from 6.6.103 before 6.6.145; from 6.12.43 before 6.12.96 — fixed in 5.10.261, 5.15.212, 5.5, 6.1.178, 6.12.96, 6.16

How to fix

Upgrade to a fixed version: Linux kernel 5.10.261, 5.15.212, 5.5, 6.1.178. Check the vendor advisory for mitigations.

References

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