Advisories › MZ Automation › ICSA-26-211-10
MZ Automation GmbH libiec61850: 8 CVEs, High 7.5
Summary
CISA reports 8 vulnerabilities in MZ Automation libiec61850. Weakness type: Out-of-bounds Read. Successful exploitation of these vulnerabilities could allow an attacker to cause a denial-of-service condition on the device. Highest CVSS v3 score: 7.5 (High), exploitable over the network.
What to do: Prioritize: MZ Automation GmbH recommends that users update to version 1.6.2.
At a glance
- Vendor
- MZ Automation
- Products
- libiec61850
- CVEs
- CVE-2026-66720, CVE-2026-66369, CVE-2026-63550, CVE-2026-65421, CVE-2026-66364, CVE-2026-66349, CVE-2026-56758, CVE-2026-66360
- Highest CVSS v3
- 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Highest CVSS v4
- –
- Known exploited (KEV)
- No CVE from this advisory is on the KEV list as of the last refresh
- Sectors (per CISA)
- Energy
- Deployed
- Worldwide
- Vendor HQ
- Germany
Vulnerabilities
| CVE | Weakness | CVSS v3 | CVSS v4 | KEV | Description (from advisory) |
|---|---|---|---|---|---|
| CVE-2026-66720 | Out-of-bounds Read | 6.5 | – | No | The GOOSE subscriber component improperly validates the UTC timestamp field in unauthenticated IEC 61850 GOOSE (EtherType 0x88B8) Layer-2 multicast messages. A specially crafted GOOSE frame containing an undersized timestamp field can trigger a heap out-of-bounds read during message processing, causing the process to crash and resulting in a denial-of-service condition. |
| CVE-2026-66369 | Out-of-bounds Read | 6.5 | – | No | The GOOSE parser contains an off-by-one boundary-handling flaw that can be triggered by a single unauthenticated Layer-2 multicast frame on the process bus. When specific GOOSE message fields are processed, the parser advances its internal buffer position incorrectly, resulting in a heap out-of-bounds read. On affected platforms, this condition reliably terminates the subscriber process and causes… |
| CVE-2026-63550 | Out-of-bounds Read | 6.5 | – | No | 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, resu… |
| CVE-2026-65421 | Out-of-bounds Read | 6.5 | – | No | The MMS BER decoder contains a flaw in decoding fixed-width BER fields (boolean/integer): an attacker-supplied length value is not validated, causing a read past the end of a heap buffer. This leads to termination of the MMS service process and a denial-of-service condition. |
| CVE-2026-66364 | Out-of-bounds Read | 6.5 | – | No | 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 d… |
| CVE-2026-66349 | Out-of-bounds Read | 6.5 | – | No | The MMS server connection handler contains a flaw in its processing of BER-encoded request data. When an MMS confirmed request PDU containing an extended BER tag is received over an established session, the decoder may advance its internal buffer incorrectly due to a missing bounds check. This results in a one byte heap out-of-bounds read and causes the MMS service process to terminate, leading to… |
| CVE-2026-56758 | Out-of-bounds Read | 6.5 | – | No | The ACSE layer contains a flaw in the processing of AARQ PDUs during MMS connection establishment. When parsing certain fields within the calling AP title, an attacker controlled length value of zero or one may cause the parser to read past the end of a heap buffer. |
| CVE-2026-66360 | Out-of-bounds Read | 7.5 | – | No | The ISO Presentation layer contains a flaw in the handling of specific parameters during normal mode negotiation. A missing length check in the processing of the encoded presentation data allows an attacker controlled field with a zero length value to trigger a bounded heap over read. This condition occurs before MMS session establishment, a crafted TCP/102 connection attempt can trigger the issue… |
Affected products (1)
- MZ Automation GmbH libiec61850: <1.6.2
Vendor fixes and mitigations (from advisory)
- Mitigation: MZ Automation GmbH recommends that users update to version 1.6.2.
Also apply CISA's standard ICS practices: minimize network exposure, keep control networks behind firewalls and isolated from business networks, and use up-to-date secure remote access.
Sources
This page is generated automatically from the CISA advisory text. It is not a substitute for the vendor's guidance; verify affected versions and fixes at the source before making changes to control systems.