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TI-2026-75355 Aliases CVE-2026-68906

Infinite loop and out-of-bounds read in libIEC61850 ACSE parsing

Priority HIGH 77CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.

Summary

libIEC61850 before 1.6.2 mishandles a truncated long-form length in parseUserInformation, so the parser skips its error check, reads the byte before the buffer and restarts the same malformed state (CWE-835). An unauthenticated remote peer can send a malformed AARE PDU during association to cause an infinite CPU loop or a one-byte out-of-bounds read (CWE-125) that aborts the process when the preceding byte is inaccessible.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

libIEC61850 is an open-source implementation of IEC 61850 client and server protocols including MMS, GOOSE, Sampled Values, and R-Session. Prior to 1.6.2, parseUserInformation in src/mms/iso_acse/acse.c checks len for zero before validating the negative bufPos returned by BerDecoder_decodeLength for a truncated long-form length. The continue path therefore swallows the error, reads buffer[-1], resets parsing to the beginning, and repeats the same malformed state. An unauthenticated remote peer can send a malformed AARE PDU during association to cause an infinite CPU loop under a normal allocator or a one-byte out-of-bounds read and process abort when the preceding byte is inaccessible. This issue is fixed in version 1.6.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00471 40th percentileScored 2026-11-07
Fix Fixed libiec61850 (mz-automation): 1.6.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MZ Automationlibiec61850before 1.6.21.6.2Patch availableCNA
  • libiec61850 VendorMZ Automation Affected before 1.6.2 Fixed in 1.6.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:mz-automation:libiec61850:*:*:*:*:*:*:*:*——MZ Automation
  • cpe:2.3:a:mz-automation:libiec61850:*:*:*:*:*:*:*:* Versions — — ·MZ Automation

Remediation

Upgrade mz-automation libiec61850 to version 1.6.2, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA libiec61850 (mz-automation) Fixed in 1.6.2

Timeline

  1. 2026-10-16 Threatist record created from CVE-2026-68906
  2. 2026-10-18 Priority changed: MEDIUM → LOW
  3. 2026-10-19 CISA SSVC decision points changed
  4. 2026-10-19 Priority changed: LOW → HIGH

References

Other 3

  • TI-2026-75345 Remote NULL dereference in libIEC61850 MMS Read crashes servers CVSS 3.1HIGH 7.5
  • TI-2026-75344 Remote information disclosure in libIEC61850 MMS file service CVSS 3.1HIGH 7.5
  • TI-2024-18824 In mz-automation libiec61850 v1.4.0, a NULL Pointer Dereference was detected in the… CVSS 3.1HIGH 7.5
  • TI-2022-05561 Infinite loop in MZ Automation libiec61850 CVSS 3.1HIGH 7.5
  • TI-2026-45011 MZ Automation lib60870 Out-of-bounds Read CVSS 4.0MEDIUM 6.9
  • TI-2026-44285 MZ Automation lib60870 Out-of-bounds Read CVSS 4.0MEDIUM 6.9
See all 64 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences