# CVE-2026-68908: libIEC61850 invalid free in MMS report serialization

Source: https://junglewise.ai/threats/cve-2026-68908-libiec61850-is-an-open-source-implementation-of-iec-61850-client  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-16. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-68908 · Severity: medium · CVSS 5.3 · Published 2026-10-16

libIEC61850 is an open-source library implementing industrial power grid communication protocols (IEC 61850). A remote attacker can crash the MMS server by writing an oversized report identifier (RptID) and then triggering report generation, exploiting a stack-based buffer management flaw that leads to an invalid memory free operation.

Technologies: [MZ Automation libIEC61850](https://junglewise.ai/threats/technologies/libiec61850). Vendors: [MZ Automation](https://junglewise.ai/threats/vendors/mz-automation).

## Quick answers

**Is CVE-2026-68908 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-68908 being exploited in the wild.

**How severe is CVE-2026-68908?** Medium severity, with a CVSS score of 5.3, published 16 October 2026.

**Which products and versions are affected?** MZ Automation libIEC61850 before 1.6.2.

**Is there a fix for CVE-2026-68908?** Yes: fixed in 1.6.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-68908 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-68908?** Check whether you run MZ Automation libIEC61850 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.6.2

## Technical details

The vulnerability exists in Reporting_RCBWriteAccessHandler which accepts an RptID longer than 129 bytes without validation. When report serialization occurs via sendNextReportEntrySegment, a stack buffer (rptIdBuf[130]) is passed to MmsValue_setVisibleString which incorrectly frees the stack-backed memory. The issue is triggered remotely via MMS protocol when a write to the report-control-block is followed by report generation.

## Affected products

- mz-automation libIEC61850 before 1.6.2

## Timeline

- 2026-10-16: disclosed

## References

- [https://github.com/mz-automation/libiec61850/commit/5b2a69f44256b8548927d8afdd7ac5f5381abe1e](https://github.com/mz-automation/libiec61850/commit/5b2a69f44256b8548927d8afdd7ac5f5381abe1e)
- [https://github.com/mz-automation/libiec61850/releases/tag/v1.6.2](https://github.com/mz-automation/libiec61850/releases/tag/v1.6.2)

## Related threats

- [libIEC61850 buffer over-read in dataset access handler](https://junglewise.ai/threats/cve-2026-68907-libiec61850-is-an-open-source-implementation-of-iec-61850-client)
- [libIEC61850 infinite loop in ACSE parseUserInformation](https://junglewise.ai/threats/cve-2026-68906-libiec61850-is-an-open-source-implementation-of-iec-61850-client)
- [libIEC61850 MMS ObtainFile double-free denial of service](https://junglewise.ai/threats/cve-2026-57446-libiec61850-is-an-open-source-implementation-of-iec-61850-client)
- [libIEC61850 NULL pointer dereference in MMS read service](https://junglewise.ai/threats/cve-2026-48741-libiec61850-is-an-open-source-implementation-of-iec-61850-client)
- [libIEC61850 MMS file service information disclosure](https://junglewise.ai/threats/cve-2026-48503-libiec61850-is-an-open-source-implementation-of-iec-61850-client)