What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-16 · updated 2026-10-19
• Weakness: CWE-125

Description

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 products

• mz-automation libiec61850: before 1.6.2

References

• https://github.com/mz-automation/libiec61850/commit/2edf2a12bf0ced6a2ac595862e3e873814983f7f
• https://github.com/mz-automation/libiec61850/releases/tag/v1.6.2
• https://github.com/mz-automation/libiec61850/security/advisories/GHSA-f7xm-q62q-22cx
• https://github.com/mz-automation/libiec61850/security/advisories/GHSA-f7xm-q62q-22cx

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