<Vulnerability name="CVE-2026-64533">
    <DocumentDistribution xml:lang="en">Copyright © 2012 Red Hat, Inc. All rights reserved.</DocumentDistribution>
    <PublicDate>2026-07-27T00:00:00</PublicDate>
    <Bugzilla id="2507401" url="https://bugzilla.redhat.com/show_bug.cgi?id=2507401" xml:lang="en:us">
kernel: fs/ntfs3: validate lcns_follow in log_replay conversion
    </Bugzilla>
    <CWE>CWE-787</CWE>
    <Details xml:lang="en:us" source="Mitre">
In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: validate lcns_follow in log_replay conversion

log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY
records when replaying version 0 restart tables.

During this conversion, the memmove() length is derived directly from
the on-disk lcns_follow field:

	memmove(&amp;dp-&gt;vcn, &amp;dp0-&gt;vcn_low,
		2 * sizeof(u64) +
				le32_to_cpu(dp-&gt;lcns_follow) * sizeof(u64));

check_rstbl() validates restart table structure, but does not constrain
per-entry lcns_follow values relative to the entry size. A malformed
filesystem image can provide an oversized lcns_follow value, causing
the conversion memmove() to access memory beyond the bounds of the
allocated restart table buffer.

The same field is later used to bound iteration over page_lcns[],
so validating lcns_follow during conversion also prevents downstream
out-of-bounds access from the same malformed metadata.

Compute the maximum valid lcns_follow from the already-validated
restart table entry size and reject entries that exceed this bound.
Reuse the existing t16/t32 scratch variables already declared in
log_replay() to avoid introducing new declarations.

[almaz.alexandrovich@paragon-software.com: fixed the conflicts]
    </Details>
    <Details xml:lang="en:us" source="Red Hat">
A flaw was found in the Linux kernel's ntfs3 filesystem driver. A local attacker could exploit this vulnerability by crafting a specially designed NTFS filesystem image. This flaw allows an attacker to cause an out-of-bounds memory write during the log replay conversion process, potentially leading to memory corruption and system instability or denial of service.
    </Details>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:10">
        <ProductName>Red Hat Enterprise Linux 10</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:6">
        <ProductName>Red Hat Enterprise Linux 6</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:7">
        <ProductName>Red Hat Enterprise Linux 7</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:7">
        <ProductName>Red Hat Enterprise Linux 7</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:9">
        <ProductName>Red Hat Enterprise Linux 9</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:9">
        <ProductName>Red Hat Enterprise Linux 9</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <References xml:lang="en:us">
https://www.cve.org/CVERecord?id=CVE-2026-64533
https://nvd.nist.gov/vuln/detail/CVE-2026-64533
https://lore.kernel.org/linux-cve-announce/2026072734-CVE-2026-64533-8c8b@gregkh/T
    </References>
</Vulnerability>