<Vulnerability name="CVE-2026-64540">
    <DocumentDistribution xml:lang="en">Copyright © 2012 Red Hat, Inc. All rights reserved.</DocumentDistribution>
    <ThreatSeverity>Moderate</ThreatSeverity>
    <PublicDate>2026-07-27T00:00:00</PublicDate>
    <Bugzilla id="2507802" url="https://bugzilla.redhat.com/show_bug.cgi?id=2507802" xml:lang="en:us">
kernel: usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup()
    </Bugzilla>
    <CVSS3 status="draft">
        <CVSS3BaseScore>5.5</CVSS3BaseScore>
        <CVSS3ScoringVector>CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H</CVSS3ScoringVector>
    </CVSS3>
    <Details xml:lang="en:us" source="Mitre">
In the Linux kernel, the following vulnerability has been resolved:

usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup()

genelink_rx_fixup() splits an aggregated RX frame into its individual
packets, using a per-packet length taken from device-supplied data. That
length is only bounded by GL_MAX_PACKET_LEN (1514); it is never compared
against how many bytes were actually received.

A malicious GeneLink (GL620A) device can therefore send a short URB whose
header claims packet_count &gt; 1 and a first packet of up to 1514 bytes.

	skb_put_data(gl_skb, packet-&gt;packet_data, size);

then copies past the end of the receive buffer and hands the adjacent slab
contents up the network stack, an out-of-bounds read that leaks kernel heap.
No privilege is required: the path runs in the usbnet RX softirq as soon as
the interface is up.

  BUG: KASAN: slab-out-of-bounds in genelink_rx_fixup (drivers/net/usb/gl620a.c:112)
  Read of size 1514 at addr ffff888011309708 by task ksoftirqd/0/14
  Call Trace:
    ...
    __asan_memcpy (mm/kasan/shadow.c:105)
    genelink_rx_fixup (include/linux/skbuff.h:2814 drivers/net/usb/gl620a.c:112)
    usbnet_bh (drivers/net/usb/usbnet.c:572 drivers/net/usb/usbnet.c:1589)
    process_one_work (kernel/workqueue.c:3322)
    bh_worker (kernel/workqueue.c:3405)
    tasklet_action (kernel/softirq.c:965)
    handle_softirqs (kernel/softirq.c:622)
    run_ksoftirqd (kernel/softirq.c:1076)
    ...

skb_pull() already verifies that the requested length fits the buffer and
returns NULL otherwise. Move it ahead of the copy and check its result, so
a packet that overruns the received data is rejected before it is read.
Well-formed frames, whose packets are fully present, are unaffected.
    </Details>
    <Details xml:lang="en:us" source="Red Hat">
A flaw was found in the Linux kernel's GeneLink (GL620A) USB network driver. A malicious GeneLink device can send specially crafted Universal Serial Bus (USB) packets that cause an out-of-bounds read vulnerability. This can lead to the disclosure of sensitive kernel memory, potentially revealing confidential system information. No special privileges are required for an attacker to exploit this vulnerability.
    </Details>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:10">
        <ProductName>Red Hat Enterprise Linux 10</ProductName>
        <FixState>Fix deferred</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" 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 impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:7">
        <ProductName>Red Hat Enterprise Linux 7</ProductName>
        <FixState>Fix deferred</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:7">
        <ProductName>Red Hat Enterprise Linux 7</ProductName>
        <FixState>Fix deferred</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <FixState>Fix deferred</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:8">
        <ProductName>Red Hat Enterprise Linux 8</ProductName>
        <FixState>Fix deferred</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:9">
        <ProductName>Red Hat Enterprise Linux 9</ProductName>
        <FixState>Fix deferred</FixState>
        <PackageName>kernel</PackageName>
    </PackageState>
    <PackageState impact="moderate" cpe="cpe:/o:redhat:enterprise_linux:9">
        <ProductName>Red Hat Enterprise Linux 9</ProductName>
        <FixState>Fix deferred</FixState>
        <PackageName>kernel-rt</PackageName>
    </PackageState>
    <References xml:lang="en:us">
https://www.cve.org/CVERecord?id=CVE-2026-64540
https://nvd.nist.gov/vuln/detail/CVE-2026-64540
https://lore.kernel.org/linux-cve-announce/2026072735-CVE-2026-64540-d315@gregkh/T
    </References>
</Vulnerability>