# CVE-2026-66281: Silicon Labs EmberZNet denial-of-service in Discover Attributes

Source: https://junglewise.ai/threats/cve-2026-66281-in-emberznet-9-1-1-and-earlier-a-malformed-discover-attributes  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-22. Updated: 2026-10-22  
License: CC BY 4.0 with a link back

CVE-2026-66281 · Severity: info · Published 2026-10-22

EmberZNet is a Zigbee protocol stack used in IoT and smart home devices. A malformed Discover Attributes command can trigger an infinite loop in devices that support manufacturer-specific clusters, causing the affected device to become unresponsive and disrupting network operations. The attacker must already be connected to the network, limiting exposure to trusted or compromised network participants.

Technologies: [Silicon Labs EmberZNet](https://junglewise.ai/threats/technologies/emberznet), [Silicon Labs SiSDK](https://junglewise.ai/threats/technologies/sisdk). Vendors: [Silicon Labs](https://junglewise.ai/threats/vendors/silicon-labs).

## Quick answers

**Is CVE-2026-66281 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-66281 being exploited in the wild.

**How severe is CVE-2026-66281?** Informational severity, published 22 October 2026.

**Which products and versions are affected?** Silicon Labs EmberZNet 9.1.1 and earlier; Silicon Labs SiSDK 2026.6.1 and earlier.

**Is there a fix for CVE-2026-66281?** Yes: fixed in SiSDK 2026.6.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-66281 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-66281?** Check whether you run Silicon Labs EmberZNet or Silicon Labs SiSDK at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in SiSDK 2026.6.2 or later

## Technical details

A malformed Discover Attributes command creates an infinite loop with an unreachable exit condition in EmberZNet's cluster handling logic. This vulnerability requires the attacker to be authenticated on the network and only affects devices supporting manufacturer-specific clusters. Exploitation results in device hang and denial of service, though watchdog mechanisms may enable recovery.

## Affected products

- Silicon Labs EmberZNet 9.1.1 and earlier
- Silicon Labs SiSDK 2026.6.1 and earlier

## Timeline

- 2026-10-22: disclosed

## References

- [https://github.com/SiliconLabsSoftware/docs-security-advisories/blob/main/Advisories/500-599/A-00000590.md](https://github.com/SiliconLabsSoftware/docs-security-advisories/blob/main/Advisories/500-599/A-00000590.md)

## Related threats

- [Silicon Labs EmberZNet out-of-bounds write in Price cluster](https://junglewise.ai/threats/cve-2026-94502-in-emberznet-9-1-1-and-earlier-a-malformed-publish-price-matrix)
- [Silicon Labs EmberZNet out-of-bounds write in Group Cluster](https://junglewise.ai/threats/cve-2026-85080-in-emberznet-9-1-1-and-earlier-a-malformed-getgroupmembership)
- [Silicon Labs EmberZNet out-of-bounds write in Simple_Desc_req](https://junglewise.ai/threats/cve-2026-85079-in-emberznet-9-1-1-and-earlier-a-malformed-simple-desc-req)
- [Silicon Labs EmberZNet denial-of-service in Price Cluster](https://junglewise.ai/threats/cve-2026-66282-in-emberznet-9-1-1-and-earlier-a-malformed-publish-billing-period)
- [Silicon Labs SiSDK denial of service in multiprotocol mode](https://junglewise.ai/threats/cve-2026-17610-silicon-labs-sisdk-denial-of-service-in-multiprotocol-mode)