Bug 2492433 (CVE-2026-52992)

Summary: CVE-2026-52992 kernel: fs/adfs: validate nzones in adfs_validate_bblk()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Advanced Disc Filing System (ADFS) component. This vulnerability allows a local attacker to cause an out-of-bounds write by providing a specially crafted ADFS disc record with a zero zone count. This can lead to memory corruption, potentially resulting in a denial of service or other unpredictable system behavior.
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Description OSIDB Bzimport 2026-06-24 18:11:49 UTC 
In the Linux kernel, the following vulnerability has been resolved:

fs/adfs: validate nzones in adfs_validate_bblk()

Reject ADFS disc records with a zero zone count during boot block
validation, before the disc record is used.

When nzones is 0, adfs_read_map() passes it to kmalloc_array(0, ...)
which returns ZERO_SIZE_PTR, and adfs_map_layout() then writes to
dm[-1], causing an out-of-bounds write before the allocated buffer.

adfs_validate_dr0() already rejects nzones != 1 for old-format
images.  Add the equivalent check to adfs_validate_bblk() for
new-format images so that a crafted image with nzones == 0 is
rejected at probe time.

Found by syzkaller.
Comment 1 Mauro Matteo Cascella 2026-06-26 11:20:32 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062444-CVE-2026-52992-af99@gregkh/T