<Vulnerability name="CVE-2026-52993">
    <DocumentDistribution xml:lang="en">Copyright © 2012 Red Hat, Inc. All rights reserved.</DocumentDistribution>
    <ThreatSeverity>Important</ThreatSeverity>
    <PublicDate>2026-06-24T00:00:00</PublicDate>
    <Bugzilla id="2492437" url="https://bugzilla.redhat.com/show_bug.cgi?id=2492437" xml:lang="en:us">
kernel: tipc: fix double-free in tipc_buf_append()
    </Bugzilla>
    <CVSS3 status="verified">
        <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-763</CWE>
    <Details xml:lang="en:us" source="Mitre">
In the Linux kernel, the following vulnerability has been resolved:

tipc: fix double-free in tipc_buf_append()

tipc_msg_validate() can potentially reallocate the skb it is validating,
freeing the old one.  In tipc_buf_append(), it was being called with a
pointer to a local variable which was a copy of the caller's skb
pointer.

If the skb was reallocated and validation subsequently failed, the error
handling path would free the original skb pointer, which had already
been freed, leading to double-free.

Fix this by checking if head now points to a newly allocated reassembled
skb.  If it does, reassign *headbuf for later freeing operations.
    </Details>
    <Details xml:lang="en:us" source="Red Hat">
A flaw was found in the Linux kernel's Transparent Inter-Process Communication (TIPC) module. This vulnerability, a double-free, occurs when the `tipc_buf_append()` function incorrectly handles memory after a socket buffer (skb) reallocation. An attacker could potentially exploit this to cause system instability or a denial of service. In some scenarios, this type of memory corruption could also lead to arbitrary code execution.
    </Details>
    <AffectedRelease cpe="cpe:/o:redhat:enterprise_linux:10.2">
        <ProductName>Red Hat Enterprise Linux 10</ProductName>
        <ReleaseDate>2026-07-28T00:00:00Z</ReleaseDate>
        <Advisory type="RHSA" url="https://access.redhat.com/errata/RHSA-2026:47017">RHSA-2026:47017</Advisory>
        <Package name="kernel">kernel-0:6.12.0-211.40.1.el10_2</Package>
    </AffectedRelease>
    <AffectedRelease cpe="cpe:/a:redhat:enterprise_linux:8::nfv">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <ReleaseDate>2026-07-24T00:00:00Z</ReleaseDate>
        <Advisory type="RHSA" url="https://access.redhat.com/errata/RHSA-2026:45116">RHSA-2026:45116</Advisory>
        <Package name="kernel-rt">kernel-rt-0:4.18.0-553.147.1.rt7.488.el8_10</Package>
    </AffectedRelease>
    <AffectedRelease cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <ReleaseDate>2026-07-24T00:00:00Z</ReleaseDate>
        <Advisory type="RHSA" url="https://access.redhat.com/errata/RHSA-2026:45115">RHSA-2026:45115</Advisory>
        <Package name="kernel">kernel-0:4.18.0-553.147.1.el8_10</Package>
    </AffectedRelease>
    <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: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-2026-52993
https://nvd.nist.gov/vuln/detail/CVE-2026-52993
https://lore.kernel.org/linux-cve-announce/2026062445-CVE-2026-52993-34a2@gregkh/T
    </References>
</Vulnerability>