<Vulnerability name="CVE-2026-64267">
    <DocumentDistribution xml:lang="en">Copyright © 2012 Red Hat, Inc. All rights reserved.</DocumentDistribution>
    <ThreatSeverity>Moderate</ThreatSeverity>
    <PublicDate>2026-07-25T00:00:00</PublicDate>
    <Bugzilla id="2507079" url="https://bugzilla.redhat.com/show_bug.cgi?id=2507079" xml:lang="en:us">
kernel: fuse: avoid 32-bit prune notification count wrap
    </Bugzilla>
    <CVSS3 status="draft">
        <CVSS3BaseScore>7.0</CVSS3BaseScore>
        <CVSS3ScoringVector>CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H</CVSS3ScoringVector>
    </CVSS3>
    <CWE>CWE-190</CWE>
    <Details xml:lang="en:us" source="Mitre">
In the Linux kernel, the following vulnerability has been resolved:

fuse: avoid 32-bit prune notification count wrap

FUSE_NOTIFY_PRUNE validates the nodeid payload length with:

    size - sizeof(outarg) != outarg.count * sizeof(u64)

On 32-bit kernels, size_t is also 32 bits, so the daemon-controlled
count multiplication can wrap.  A prune notification with count
0x20000000 and no nodeid payload passes the check, enters the copy
loop, and asks the device copy path to read nodeids that are not
present in the userspace write buffer.  In QEMU this reaches the
fuse_copy_fill() BUG_ON(!err) path.

Validate the payload length with array_size() instead.  That accepts
exactly the same valid messages, but avoids wrapping arithmetic before
the copy loop consumes the count.
    </Details>
    <Details xml:lang="en:us" source="Red Hat">
A flaw was found in the Linux kernel's Filesystem in Userspace (FUSE) component. On 32-bit systems, an integer overflow vulnerability exists in the handling of `FUSE_NOTIFY_PRUNE` messages. A malicious FUSE daemon or a local user could craft a prune notification with a specific count, causing an integer overflow during payload length validation. This can lead to the kernel attempting to read non-existent data, resulting in a system crash and a Denial of Service (DoS).
    </Details>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:10">
        <ProductName>Red Hat Enterprise Linux 10</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:6">
        <ProductName>Red Hat Enterprise Linux 6</ProductName>
        <FixState>Out of support scope</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:7">
        <ProductName>Red Hat Enterprise Linux 7</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:7">
        <ProductName>Red Hat Enterprise Linux 7</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:9">
        <ProductName>Red Hat Enterprise Linux 9</ProductName>
        <FixState>Not affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState 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-2026-64267
https://nvd.nist.gov/vuln/detail/CVE-2026-64267
https://lore.kernel.org/linux-cve-announce/2026072559-CVE-2026-64267-a265@gregkh/T
    </References>
</Vulnerability>