# CVE-2026-16225: davenardella snap7 s7_peer.cpp NegotiatePDULength out-of-bounds write

> Remote attackers can trigger an out-of-bounds write in snap7's PDU negotiation, potentially leading to code execution or crashes.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Jul 2026
- **Updated:** 20 Jul 2026
- **Also known as:** GHSA-cc6f-5g4h-cf75

## What is CVE-2026-16225?

CVE-2026-16225 is a medium-severity memory corruption vulnerability in davenardella snap7, published on 19 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A security flaw has been discovered in davenardella snap7 up to 1.4.3. The impacted element is the function TSnap7Peer::NegotiatePDULength of the file src/core/s7_peer.cpp. The manipulation of the argument PDULength results in out-of-bounds write. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks.

Weakness: CWE-787 (Out-of-bounds Write), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-16225?


## How do I fix CVE-2026-16225?

No fix has been published for CVE-2026-16225 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-16225 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-16225 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-16225 and fix it if it is affected.

What it is: CVE-2026-16225 is a medium-severity memory corruption vulnerability in davenardella snap7, published on 19 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-16225 exists.

Affected product: davenardella snap7. 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-2026-16225/ (Markdown: https://insights.sbomify.com/CVE-2026-16225/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-16225
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-16225
- OSV: https://osv.dev/vulnerability/CVE-2026-16225

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-16225/
Summaries are generated and may contain mistakes; the official description above is the record.