Bug 2507058 (CVE-2026-64360)

Summary: CVE-2026-64360 kernel: hfs/hfsplus: zero-initialize buffer in hfs_bnode_read
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel. The `hfs_bnode_read()` function within the HFS/HFS+ filesystem driver could return without fully initializing a buffer. This could lead to the use of uninitialized memory, potentially causing unpredictable system behavior or the disclosure of sensitive information.
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Description OSIDB Bzimport 2026-07-25 10:02:50 UTC 
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.
Comment 1 Mauro Matteo Cascella 2026-07-29 22:03:40 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072520-CVE-2026-64360-402f@gregkh/T