CVE-2026-63550 MZ Automation libiec61850 Out-of-bounds Read
A crafted BER-encoded message can cause a heap out-of-bounds read in the MMS decoder, leading to a denial-of-service in IEC 61850 systems.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-63550?
CVE-2026-63550 is a high-severity memory corruption vulnerability in MZ Automation GmbH libiec61850, published on 30 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The MMS BER decoder contains a boundary-handling flaw in the processing of certain fields within confirmed-request messages. When a crafted BER-encoded element is received over an established MMS session (TCP port 102), the decoder may advance its internal read position incorrectly, leading to a heap out-of-bounds read. This condition causes the MMS handling process to terminate unexpectedly, resulting in a denial-of-service.
Weakness: CWE-125
Which versions are affected by CVE-2026-63550?
How do I fix CVE-2026-63550?
No fix has been published for CVE-2026-63550 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-63550 being exploited?
There is no known exploitation of CVE-2026-63550 in the wild and no public exploit code.
Sources
Also known as GHSA-mgh9-x48v-5vx9.