<Vulnerability name="CVE-2026-53343">
    <DocumentDistribution xml:lang="en">Copyright © 2012 Red Hat, Inc. All rights reserved.</DocumentDistribution>
    <PublicDate>2026-07-01T00:00:00</PublicDate>
    <Bugzilla id="2495933" url="https://bugzilla.redhat.com/show_bug.cgi?id=2495933" xml:lang="en:us">
kernel: ARM: 9475/1: entry: use byte load for KASAN VMAP stack shadow
    </Bugzilla>
    <CWE>CWE-468</CWE>
    <Details xml:lang="en:us" source="Mitre">
In the Linux kernel, the following vulnerability has been resolved:

ARM: 9475/1: entry: use byte load for KASAN VMAP stack shadow

Commit 44e9a3bb76e5 ("ARM: 9430/1: entry: Do a dummy read from
VMAP shadow") added a dummy read from the KASAN VMAP stack shadow in
__switch_to(). The read uses ldr, but the KASAN shadow address is
byte-granular and is not guaranteed to be word aligned.

ARMv5 faults unaligned word loads. With CONFIG_KASAN_VMALLOC and
CONFIG_VMAP_STACK enabled, ARM926/VersatilePB crashes in __switch_to()
with an alignment exception before reaching init.

Use ldrb for the dummy shadow access. The code only needs to fault in the
shadow mapping if the stack shadow is missing, so a byte load is sufficient
and matches the granularity of KASAN shadow memory.
    </Details>
    <Details xml:lang="en:us" source="Red Hat">
A flaw was found in the Linux kernel. On ARMv5 systems configured with Kernel Address Sanitizer (KASAN) for virtual memory allocated (VMAP) stack shadow, a memory access operation could attempt to read data from an unaligned memory address. This unaligned access leads to an alignment exception, causing the system to crash. This vulnerability results in a Denial of Service (DoS) for affected systems.
    </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>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</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-2026-53343
https://nvd.nist.gov/vuln/detail/CVE-2026-53343
https://lore.kernel.org/linux-cve-announce/2026070144-CVE-2026-53343-e76a@gregkh/T
    </References>
</Vulnerability>