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

{
  "id": "78f3acef06acaf5eb95cc16bb23a419c693766c473ebb7f917fd9ef7dcd30b82",
  "url": "https://osv.dev/vulnerability/CVE-2026-64540",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup()",
    "summary": "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 > 1 and a first packet of up to 1514 bytes. skb_put_data(gl_skb, packet->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 ",
    "evidence": "osv:CVE-2026-64540",
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    "severity": "high",
    "structured": {
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      "aliases": [
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      "metrics": [
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          "type": "CVSS_V3",
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      "modified": "2026-10-28T02:30:32.770882152Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0575599e451aff3c5329922562374a2cab25fc51",
        "https://git.kernel.org/stable/c/0a7d9c7c5f1f208c523abbb4db6aea7bc1fad3db",
        "https://git.kernel.org/stable/c/255d03551f94c7bdd86c7d9181a70b21917d829f",
        "https://git.kernel.org/stable/c/3ef79fa3860e644c8de7834fa7300e1c58f38862",
        "https://git.kernel.org/stable/c/4359376e6238d89977a35086e47ca3b07f43e850",
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        "https://git.kernel.org/stable/c/8ff7f2a6da4fccaa5cc9be7251a24e71e29fbd1a",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64540.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64540",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64540.json"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 500076,
  "published_at": "2026-07-27T20:10:33.905+00:00"
}