# CVE-2025-38331: net: ethernet: cortina: Use TOE/TSO on all TCP

CVE-2025-38331 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-38331, released July 10, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-38331
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0036
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 10, 2025
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-38331

## Description

In the Linux kernel, the following vulnerability has been resolved:  net: ethernet: cortina: Use TOE/TSO on all TCP  It is desireable to push the hardware accelerator to also process non-segmented TCP frames: we pass the skb->len to the "TOE/TSO" offloader and it will handle them.  Without this quirk the driver becomes unstable and lock up and and crash.  I do not know exactly why, but it is probably due to the TOE (TCP offload engine) feature that is coupled with the segmentation feature - it is not possible to turn one part off and not the other, either both TOE and TSO are active, or neither of them.  Not having the TOE part active seems detrimental, as if that hardware feature is not really supposed to be turned off.  The datasheet says:    "Based on packet parsing and TCP connection/NAT table    lookup results, the NetEngine puts the packets    belonging to the same TCP connection to the same queue    for the software to process. The NetEngine puts    incoming packets to the buffer or series of buffers    for a jumbo packet. With this hardware acceleration,    IP/TCP header parsing, checksum validation and    connection lookup are offloaded from the software    processing."  After numerous tests with the hardware locking up after something between minutes and hours depending on load using iperf3 I have concluded this is necessary to stabilize the hardware.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.147-1 | [DEBIAN-CVE-2025-38331](https://patchblox.com/security/data/fix/linux/debian-cve-2025-38331.md) | Jul 10, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.12.35-1 | [DEBIAN-CVE-2025-38331](https://patchblox.com/security/data/fix/linux/debian-cve-2025-38331.md) | Jul 10, 2025 |
| Linux | linux Debian 14 | 6.12.35-1 | [DEBIAN-CVE-2025-38331](https://patchblox.com/security/data/fix/linux/debian-cve-2025-38331.md) | Jul 10, 2025 |

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