Description
In the Linux kernel, the following vulnerability has been resolved:
net: usb: cx82310_eth: drop URB after 0xffff reboot sentinel to prevent partial_data heap overflow
The 0xffff length sentinel detects a router reboot and schedules
re-enabling of ethernet mode, but then falls through to the rest
of the loop body. The next check is
} else if (len > CX82310_MTU) {
which is the else of the just-matched if -- it never fires for
len == 0xffff. The MTU bound that normally caps the
incomplete-packet save path is silently bypassed.
With 0xffff > skb->len always true (rx_urb_size is 4096), the
incomplete-packet branch saves dev->partial_len = skb->len bytes
into dev->partial_data. partial_data is kmalloc(hard_mtu) =
kmalloc(CX82310_MTU + 2) = 1516 bytes, but skb->len after the
2-byte header pull can be up to 4094. A device that sends a
4096-byte URB starting with [0xff 0xff] therefore copies 4094
device-provided bytes into a buffer allocated for 1516 bytes,
exceeding its requested size by 2578 bytes.
The next URB then reads dev->partial_len (4094) back from the same
1516-byte buffer and dev->partial_rem (65535 - 4094 = 61441) from
the new URB's ~4KB skb, both well past their allocations, and
delivers the spliced result as a 64KB "frame" to the network
stack.
Bail out of rx_fixup after scheduling the re-enable work; the
remainder of a reboot-marker URB is not meaningful packet data.
This restores the invariant that partial_len < CX82310_MTU + 2 on
the save path, since every other route there has already passed
the MTU check.
net: usb: cx82310_eth: drop URB after 0xffff reboot sentinel to prevent partial_data heap overflow
The 0xffff length sentinel detects a router reboot and schedules
re-enabling of ethernet mode, but then falls through to the rest
of the loop body. The next check is
} else if (len > CX82310_MTU) {
which is the else of the just-matched if -- it never fires for
len == 0xffff. The MTU bound that normally caps the
incomplete-packet save path is silently bypassed.
With 0xffff > skb->len always true (rx_urb_size is 4096), the
incomplete-packet branch saves dev->partial_len = skb->len bytes
into dev->partial_data. partial_data is kmalloc(hard_mtu) =
kmalloc(CX82310_MTU + 2) = 1516 bytes, but skb->len after the
2-byte header pull can be up to 4094. A device that sends a
4096-byte URB starting with [0xff 0xff] therefore copies 4094
device-provided bytes into a buffer allocated for 1516 bytes,
exceeding its requested size by 2578 bytes.
The next URB then reads dev->partial_len (4094) back from the same
1516-byte buffer and dev->partial_rem (65535 - 4094 = 61441) from
the new URB's ~4KB skb, both well past their allocations, and
delivers the spliced result as a 64KB "frame" to the network
stack.
Bail out of rx_fixup after scheduling the re-enable work; the
remainder of a reboot-marker URB is not meaningful packet data.
This restores the invariant that partial_len < CX82310_MTU + 2 on
the save path, since every other route there has already passed
the MTU check.
Published:
2026-09-25
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
No advisories yet.
References
History
Fri, 25 Sep 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-122 |
Fri, 25 Sep 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net: usb: cx82310_eth: drop URB after 0xffff reboot sentinel to prevent partial_data heap overflow The 0xffff length sentinel detects a router reboot and schedules re-enabling of ethernet mode, but then falls through to the rest of the loop body. The next check is } else if (len > CX82310_MTU) { which is the else of the just-matched if -- it never fires for len == 0xffff. The MTU bound that normally caps the incomplete-packet save path is silently bypassed. With 0xffff > skb->len always true (rx_urb_size is 4096), the incomplete-packet branch saves dev->partial_len = skb->len bytes into dev->partial_data. partial_data is kmalloc(hard_mtu) = kmalloc(CX82310_MTU + 2) = 1516 bytes, but skb->len after the 2-byte header pull can be up to 4094. A device that sends a 4096-byte URB starting with [0xff 0xff] therefore copies 4094 device-provided bytes into a buffer allocated for 1516 bytes, exceeding its requested size by 2578 bytes. The next URB then reads dev->partial_len (4094) back from the same 1516-byte buffer and dev->partial_rem (65535 - 4094 = 61441) from the new URB's ~4KB skb, both well past their allocations, and delivers the spliced result as a 64KB "frame" to the network stack. Bail out of rx_fixup after scheduling the re-enable work; the remainder of a reboot-marker URB is not meaningful packet data. This restores the invariant that partial_len < CX82310_MTU + 2 on the save path, since every other route there has already passed the MTU check. | |
| Title | net: usb: cx82310_eth: drop URB after 0xffff reboot sentinel to prevent partial_data heap overflow | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-25T10:23:43.906Z
Reserved: 2026-09-25T10:19:56.070Z
Link: CVE-2026-98025
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-25T11:17:31.110
Modified: 2026-09-25T11:17:31.110
Link: CVE-2026-98025
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-09-25T16:30:15Z
Weaknesses
-
CWE-122
Heap-based Buffer Overflow