CVE-2026-66364 MZ Automation libiec61850 Out-of-bounds Read
An attacker can cause a denial of service in libiec61850 subscribers by sending a crafted multicast frame that triggers an out-of-bounds read.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66364?
CVE-2026-66364 is a high-severity denial of service vulnerability in MZ Automation GmbH libiec61850, published on 30 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The GOOSE payload parser contains a boundary handling flaw that can be triggered by a single unauthenticated Layer 2 multicast frame on the process bus. When processing specific payload fields, an attacker controlled inner element length may exceed its enclosing length, causing the parser to over read by one byte. This out-of-bounds read reliably terminates the subscriber process, resulting in a denial-of-service condition.
Weakness: CWE-125
Which versions are affected by CVE-2026-66364?
How do I fix CVE-2026-66364?
No fix has been published for CVE-2026-66364 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-66364 being exploited?
There is no known exploitation of CVE-2026-66364 in the wild and no public exploit code.
Sources
Also known as GHSA-hw99-2wcp-34xq.