CVE-2026-68906 — libIEC61850: Infinite loop and out-of-bounds read in ACSE parseUserInformation when parsing a malformed AARE PDU

Description (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.

Affected (CNA)

Vendor / product	Versions
mz-automation / libiec61850	affected < 1.6.2

CWE

CWE-125, CWE-835

References

ADP enrichment

CISA-ADP

No English description supplied.

https://github.com/mz-automation/libiec61850/security/advisories/GHSA-f7xm-q62q-22cx