# CVE-2026-51218: Memory corruption in n/a

> A heap buffer overflow in snap7 allows attackers to cause a Denial of Service via crafted packets, affecting systems using this S7 communication library.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Jun 2026
- **Updated:** 30 Jul 2026
- **Also known as:** GHSA-6m46-rpq9-jh59

## What is CVE-2026-51218?

CVE-2026-51218 is a high-severity memory corruption vulnerability in n/a, published on 29 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A heap buffer overflow in the TS7Worker::PerformFunctionWrite() function (/core/s7_server.cpp) of snap7 v1.4.3 allows attackers to cause a Denial of Service (DoS) via a crafted packet.

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

## Which versions are affected by CVE-2026-51218?


## How do I fix CVE-2026-51218?

No fix has been published for CVE-2026-51218 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-51218 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-51218 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-51218 and fix it if it is affected.

What it is: CVE-2026-51218 is a high-severity memory corruption vulnerability in n/a, published on 29 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-51218 exists.

Affected product: n/a. 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-2026-51218/ (Markdown: https://insights.sbomify.com/CVE-2026-51218/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-51218
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-51218
- OSV: https://osv.dev/vulnerability/CVE-2026-51218

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-51218/
Summaries are generated and may contain mistakes; the official description above is the record.