CVE-2026-56758

Adjacent-network crash via short AP-title fields

Published Jul 30, 2026 · Updated Jul 30, 2026

Out-of-bounds read in libIEC61850 before 1.6.2 allows attackers to crash MMS servers via a malformed AARQ PDU from an adjacent network. The ACSE parseAarqPdu path accepts a zero- or one-byte length in calling AP-title fields and reads beyond the heap buffer during MMS connection establishment. The server must expose MMS connection handling to the attacker's network segment; the documented impact is a service crash, with no confidentiality or integrity effect.

CVSS severity6.9
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in libIEC61850 before 1.6.2 allows attackers to crash MMS servers via a malformed AARQ PDU from an adjacent network. The ACSE parseAarqPdu path accepts a zero- or one-byte length in calling AP-title fields and reads beyond the heap buffer during MMS connection establishment. The server must expose MMS connection handling to the attacker's network segment; the documented impact is a service crash, with no confidentiality or integrity effect.

The record

CVE
CVE-2026-56758
Published
Jul 30, 2026
Updated
Jul 30, 2026
Vendor
MZ Automation GmbH
Product
libIEC61850
Classifications
CWE-125, T1499
Attack vector
adjacent
Privileges
Unavailable

Timeline

How it unfolded

  1. Jul 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.6.2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesUnavailable in this record.

What is affected?

MZ Automation GmbH · libIEC61850version=0 <1.6.2

Published CVSS scores

6.9ICS-CERTCVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
6.5ICS-CERTCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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