<Vulnerability name="CVE-2026-53185">
    <DocumentDistribution xml:lang="en">Copyright © 2012 Red Hat, Inc. All rights reserved.</DocumentDistribution>
    <ThreatSeverity>Moderate</ThreatSeverity>
    <PublicDate>2026-06-25T00:00:00</PublicDate>
    <Bugzilla id="2492735" url="https://bugzilla.redhat.com/show_bug.cgi?id=2492735" xml:lang="en:us">
kernel: zram: fix use-after-free in zram_bvec_write_partial()
    </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-364</CWE>
    <Details xml:lang="en:us" source="Mitre">
In the Linux kernel, the following vulnerability has been resolved:

zram: fix use-after-free in zram_bvec_write_partial()

zram_read_page() picks the sync or async backing device read path based on
whether the parent bio is NULL.  zram_bvec_write_partial() passes its
parent bio down, so for ZRAM_WB slots the read is dispatched
asynchronously and zram_read_page() returns 0 while the bio is still in
flight.  The caller then runs memcpy_from_bvec(), zram_write_page() and
__free_page() on the buffer, leaving the async read to write into a freed
page.

zram_bvec_read_partial() was switched to NULL in commit 4e3c87b9421d
("zram: fix synchronous reads") for the same reason; the write_partial
counterpart was missed.
    </Details>
    <Details xml:lang="en:us" source="Red Hat">
A flaw was found in the Linux kernel, specifically within the zram module. This vulnerability is a use-after-free error, where the system attempts to use a piece of memory after it has been freed. This occurs when the `zram_bvec_write_partial()` function allows an asynchronous read to write into a page that has already been deallocated. Such a flaw can lead to system instability, causing crashes, or in some scenarios, could be exploited by a local attacker to escalate privileges or execute arbitrary code.
    </Details>
    <Statement xml:lang="en:us">
A use-after-free write can occur in zram_bvec_write_partial() when zram_read_page() is called with a parent bio and selects the asynchronous backing device read path for ZRAM_WB slots. The function can return while the read bio is still in flight, after which the caller updates the temporary page, writes it back, and frees it. The pending asynchronous read may then complete into the freed page, causing kernel memory corruption. For the CVSS the PR:L is used because triggering can be possible from a local user context once zram writeback is configured, for example through swap or block I/O activity, even though initial writeback setup is usually administrative.
    </Statement>
    <Mitigation xml:lang="en:us">
To mitigate this issue, prevent module zram from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
    </Mitigation>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:10">
        <ProductName>Red Hat Enterprise Linux 10</ProductName>
        <FixState>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>Affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <FixState>Affected</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:9">
        <ProductName>Red Hat Enterprise Linux 9</ProductName>
        <FixState>Affected</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState cpe="cpe:/o:redhat:enterprise_linux:9">
        <ProductName>Red Hat Enterprise Linux 9</ProductName>
        <FixState>Affected</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <References xml:lang="en:us">
https://www.cve.org/CVERecord?id=CVE-2026-53185
https://nvd.nist.gov/vuln/detail/CVE-2026-53185
https://lore.kernel.org/linux-cve-announce/2026062556-CVE-2026-53185-0922@gregkh/T
    </References>
</Vulnerability>