# CVE-2025-3845: markparticle WebServer buffer.cpp HasWritten buffer overflow

> Remote attackers can trigger a buffer overflow in markparticle WebServer via the HasWritten function, potentially leading to code execution or service disruption.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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:** 21 Apr 2025
- **Updated:** 22 Apr 2025
- **Also known as:** GHSA-8q95-7vjm-3mfq

## What is CVE-2025-3845?

CVE-2025-3845 is a medium-severity memory corruption vulnerability in markparticle WebServer, published on 21 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in markparticle WebServer up to 1.0. It has been declared as critical. Affected by this vulnerability is the function Buffer::HasWritten of the file code/buffer/buffer.cpp. The manipulation of the argument writePos_ leads to buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2025-3845?

It affects 1 product.


Products: Markparticle Webserver.

## How do I fix CVE-2025-3845?

No fix has been published for CVE-2025-3845 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-3845 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-3845 exists.

## Other vulnerabilities in markparticle WebServer

- [CVE-2025-3846](https://insights.sbomify.com/CVE-2025-3846/): markparticle WebServer Registration httprequest.cpp sql injection (medium 6.9)
- [CVE-2025-3847](https://insights.sbomify.com/CVE-2025-3847/): markparticle WebServer Login httprequest.cpp sql injection (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-3845 and fix it if it is affected.

What it is: CVE-2025-3845 is a medium-severity memory corruption vulnerability in markparticle WebServer, published on 21 Apr 2025. 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-2025-3845 exists.

Affected product: markparticle WebServer. 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-2025-3845/ (Markdown: https://insights.sbomify.com/CVE-2025-3845/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-3845
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-3845
- OSV: https://osv.dev/vulnerability/CVE-2025-3845

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-3845/
Summaries are generated and may contain mistakes; the official description above is the record.