---
id: "CVE-2026-68908"
kind: "vulnerability"
aliases: ["CVE-2026-68908"]
title: "libIEC61850: oversized report ID write crashes server via invalid free"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["c", "energy-automation", "iec-61850", "industrial-control", "libiec61850", "package"]
not_affected_if: ["client-only-use", "library-version-1.6.2-or-later"]
published_at: "2026-10-16T16:20:01+00:00"
first_seen_at: "2026-10-23T21:57:13+00:00"
updated_at: "2026-10-25T04:27:15+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68908", "first_seen_at": "2026-10-23T21:57:13+00:00"}]
---

# libIEC61850: oversized report ID write crashes server via invalid free

libIEC61850 is an open-source IEC 61850 client and server library. Before version 1.6.2, a remote client can write an RptID longer than 129 bytes, and a later report generation frees a stack-backed buffer, causing an invalid free and a server crash.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the libIEC61850 version in use, for example with `grep -r libiec61850` in build files or `pkg-config --modversion iec61850`
- Confirm whether the server exposes MMS report control blocks to remote clients (the write path requires a connected client)

## Fix

- Upgrade libIEC61850 to `1.6.2` or later

## Timeline

- 2026-10-23T21:57:13+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-68908

## From the sources

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, Reporting_RCBWriteAccessHandler accepts an RptID longer than 129 bytes in the report-control-block write path. When GI later causes sendNextReportEntrySegment to serialize the report, the function wraps rptIdBuf[130] as a temporary MmsValue and passes it to MmsValue_setVisibleString. The setter's resize path frees the stack-backed buffer, allowing a remote client to trigger an invalid free and server crash by writing the oversized RptID and then generating a report. This issue is fixed in version 1.6.2.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_