CVE-2026-64540 (GCVE-0-2026-64540)
Vulnerability from cvelistv5
Published
2026-07-27 20:10
Modified
2026-08-17 04:57
Severity ?
VLAI Severity ?
EPSS score ?
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 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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f Version: 47ee3051c856cc2aa95d35d577a8cb37279d540f |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/usb/gl620a.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "47ee3051c856cc2aa95d35d577a8cb37279d540f",
"versionType": "git"
},
{
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{
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{
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]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/usb/gl620a.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.14"
},
{
"lessThan": "2.6.14",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
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"versionStartIncluding": "2.6.14",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
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{
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{
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},
{
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup()\n\ngenelink_rx_fixup() splits an aggregated RX frame into its individual\npackets, using a per-packet length taken from device-supplied data. That\nlength is only bounded by GL_MAX_PACKET_LEN (1514); it is never compared\nagainst how many bytes were actually received.\n\nA malicious GeneLink (GL620A) device can therefore send a short URB whose\nheader claims packet_count \u003e 1 and a first packet of up to 1514 bytes.\n\n\tskb_put_data(gl_skb, packet-\u003epacket_data, size);\n\nthen copies past the end of the receive buffer and hands the adjacent slab\ncontents up the network stack, an out-of-bounds read that leaks kernel heap.\nNo privilege is required: the path runs in the usbnet RX softirq as soon as\nthe interface is up.\n\n BUG: KASAN: slab-out-of-bounds in genelink_rx_fixup (drivers/net/usb/gl620a.c:112)\n Read of size 1514 at addr ffff888011309708 by task ksoftirqd/0/14\n Call Trace:\n ...\n __asan_memcpy (mm/kasan/shadow.c:105)\n genelink_rx_fixup (include/linux/skbuff.h:2814 drivers/net/usb/gl620a.c:112)\n usbnet_bh (drivers/net/usb/usbnet.c:572 drivers/net/usb/usbnet.c:1589)\n process_one_work (kernel/workqueue.c:3322)\n bh_worker (kernel/workqueue.c:3405)\n tasklet_action (kernel/softirq.c:965)\n handle_softirqs (kernel/softirq.c:622)\n run_ksoftirqd (kernel/softirq.c:1076)\n ...\n\nskb_pull() already verifies that the requested length fits the buffer and\nreturns NULL otherwise. Move it ahead of the copy and check its result, so\na packet that overruns the received data is rejected before it is read.\nWell-formed frames, whose packets are fully present, are unaffected."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.1,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:A - The gl620a driver is a FLAG_POINTTOPOINT network interface, and the malformed aggregation header is received network data generated by the peer host on the other end of the GeneLink host-to-host cable, processed in the usbnet RX softirq. The attack is confined to that directly attached link segment, making it logically adjacent rather than routable or purely physical.\nAC:L - The attacker fully controls the frame contents and only needs to send an 18-byte URB declaring packet_count \u003e 1 with a first packet_length of up to 1514; the missing bounds check is deterministic with no race, memory-layout, or timing dependency.\nPR:N - No credentials or privileges on the target are required \u2014 the parse runs unconditionally in the RX softirq for any frame received once the interface is up, with no capability or authentication check anywhere on the usbnet_bh -\u003e rx_process -\u003e rx_fixup path.\nUI:N - No victim action is needed beyond the interface being in its normal operational state, which is inherent to a host-to-host link cable in use and is done automatically by NetworkManager/systemd-networkd.\nS:U - The over-read and the leaked memory stay within the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Up to ~47 KB of adjacent kernel heap is read past the valid received data and delivered up the network stack as an Ethernet frame, exfiltrating arbitrary slab contents (prior packet data, keys, pointers) to the attacker and to any local packet capture \u2014 an unbounded, repeatable kernel memory disclosure.\nI:N - The defect is strictly a read; gl_skb is allocated with alloc_skb(size) before skb_put_data() copies exactly size bytes, so no kernel memory is written out of bounds or otherwise modified.\nA:H - With rx_urb_size reduced the read runs tens of kilobytes past a small slab object and can touch unmapped memory from softirq context, and on hardened kernels the KASAN slab-out-of-bounds report (as captured in the fix commit) panics the machine; the attacker can repeat it with every frame."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:57:16.687Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/255d03551f94c7bdd86c7d9181a70b21917d829f"
},
{
"url": "https://git.kernel.org/stable/c/4359376e6238d89977a35086e47ca3b07f43e850"
},
{
"url": "https://git.kernel.org/stable/c/8624e179fa3ce23c2fbd1a198ce30764b73f054a"
},
{
"url": "https://git.kernel.org/stable/c/573418f7ea8f859a841417eb4b915594094fd967"
},
{
"url": "https://git.kernel.org/stable/c/0575599e451aff3c5329922562374a2cab25fc51"
},
{
"url": "https://git.kernel.org/stable/c/0a7d9c7c5f1f208c523abbb4db6aea7bc1fad3db"
},
{
"url": "https://git.kernel.org/stable/c/3ef79fa3860e644c8de7834fa7300e1c58f38862"
},
{
"url": "https://git.kernel.org/stable/c/8ff7f2a6da4fccaa5cc9be7251a24e71e29fbd1a"
}
],
"title": "usbnet: gl620a: fix out-of-bounds read in genelink_rx_fixup()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64540",
"datePublished": "2026-07-27T20:10:33.905Z",
"dateReserved": "2026-07-19T15:36:31.795Z",
"dateUpdated": "2026-08-17T04:57:16.687Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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