# CVE-2026-63362: o6 Automation open62541 Integer Underflow

> A remote attacker can cause a denial of service in open62541 via a crafted UDP packet due to an integer underflow in PubSub signature verification.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Jul 2026
- **Updated:** 31 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-63362, GHSA-qv76-j3j3-2f94, UBUNTU-CVE-2026-63362

## What is CVE-2026-63362?

CVE-2026-63362 is a high-severity vulnerability in o6 Automation open62541, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An unsigned integer underflow in the PubSub signature verification path 
in open62541 may allow a remote attacker to cause a denial of service 
via a crafted UDP packet.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-63362?


## How do I fix CVE-2026-63362?

No fix has been published for CVE-2026-63362 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-63362 being exploited?

There is no known exploitation of CVE-2026-63362 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63362 and fix it if it is affected.

What it is: CVE-2026-63362 is a high-severity vulnerability in o6 Automation open62541, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-63362 in the wild and no public exploit code.

Affected product: o6 Automation open62541. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63362/ (Markdown: https://insights.sbomify.com/CVE-2026-63362/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63362
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63362
- OSV: https://osv.dev/vulnerability/CVE-2026-63362

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63362/
Summaries are generated and may contain mistakes; the official description above is the record.