KEVWire

Security intelligence, with context.

Response snapshot Nov 3, 2026, 21:16 UTC

Back to the wire
Permalink
VulnerabilityCVE-2026-64540

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

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.

At a glance

Exploited
Not known
Severity
8.1 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-64540 (opens a new tab)

What happened

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.

Continue reading

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 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.

Scores and how they were measured

CVSS base severity

8.1

Version 3.1As of

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-64540 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 3). Linux kernel: usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup() (CVE-2026-64540). https://kevwire.com/record/CVE-2026-64540

MLA

"Linux kernel: usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup() (CVE-2026-64540)." KEVWire, 3 Nov. 2026, kevwire.com/record/CVE-2026-64540.

Chicago

KEVWire. "Linux kernel: usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup() (CVE-2026-64540)." Last modified November 3, 2026. https://kevwire.com/record/CVE-2026-64540.

Evidence summary (plain text)

Linux kernel: usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup() (Jul 27, 2026).
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.
CVSS 8.1 (version 3.1; evidence as of Nov 3, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-64540).
Sources:
NVD CVE-2026-64540: https://nvd.nist.gov/vuln/detail/CVE-2026-64540
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T18:06:04.789Z&lastModEndDate=2026-11-03T19:40:57.574Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T17:35:57.416Z&lastModEndDate=2026-11-03T19:05:57.748Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T17:01:00.112Z&lastModEndDate=2026-11-03T18:35:55.788Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-64540.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 3, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Awaiting Analysis. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

Record JSON

Your account

Email alerts

Email alerts are coming as part of KEVWire Premium: join the waitlist. To follow your stack today, use its RSS feed, which honors your filters, or connect an AI agent through the API.

Suggest an improvement

Ideas, missing sources, corrections, and bugs are all welcome. No account needed. Suggestions are reviewed by a person before anything changes.

Record details

Record detail