# CVE-2026-18368: Heap buffer overflow in Modbusgwd

> A remote unauthenticated attacker can cause a denial of service in Teltonika RUTOS devices via a heap buffer overflow in the Modbus gateway.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:A/AC:L/AT:P/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Aug 2026
- **Updated:** 13 Aug 2026
- **Also known as:** GHSA-26g8-9jvg-gfw6

## What is CVE-2026-18368?

CVE-2026-18368 is a medium-severity memory corruption vulnerability in Teltonika Networks RUTOS, published on 13 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In Teltonika Networks RUTOS devices, a vulnerability exists in modbusgwd
 due to improper handling of Modbus TCP request data. A remote, 
unauthenticated attacker with access to the affected service could 
trigger a heap-based buffer overflow, resulting in a denial of service.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-18368?


## How do I fix CVE-2026-18368?

No fix has been published for CVE-2026-18368 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18368 being exploited?

There is no known exploitation of CVE-2026-18368 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18368 and fix it if it is affected.

What it is: CVE-2026-18368 is a medium-severity memory corruption vulnerability in Teltonika Networks RUTOS, published on 13 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-18368 in the wild and no public exploit code.

Affected product: Teltonika Networks RUTOS. 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-2026-18368/ (Markdown: https://insights.sbomify.com/CVE-2026-18368/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18368
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18368
- OSV: https://osv.dev/vulnerability/CVE-2026-18368

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18368/
Summaries are generated and may contain mistakes; the official description above is the record.