Bug 2481961 (CVE-2026-45935)

Summary: CVE-2026-45935 kernel: fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: unspecified    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's NTFS3 filesystem driver. Insufficient bounds checking when processing log records in the `DeleteIndexEntryRoot` function allows a local attacker to provide a maliciously large entry size. This can lead to a heap buffer overflow, a type of memory corruption, which may result in a denial of service or potentially arbitrary code execution.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-05-27 15:04:28 UTC
In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot

In the 'DeleteIndexEntryRoot' case of the 'do_action' function, the
entry size ('esize') is retrieved from the log record without adequate
bounds checking.

Specifically, the code calculates the end of the entry ('e2') using:
    e2 = Add2Ptr(e1, esize);

It then calculates the size for memmove using 'PtrOffset(e2, ...)',
which subtracts the end pointer from the buffer limit. If 'esize' is
maliciously large, 'e2' exceeds the used buffer size. This results in
a negative offset which, when cast to size_t for memmove, interprets
as a massive unsigned integer, leading to a heap buffer overflow.

This commit adds a check to ensure that the entry size ('esize') strictly
fits within the remaining used space of the index header before performing
memory operations.