# CVE-2011-10029: Solar FTP Server <= 2.1.1 Malformed USER Denial of Service

> A remote attacker can crash the Solar FTP Server by sending a malformed USER command, causing a denial of service.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/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:** 20 Aug 2025
- **Updated:** 15 May 2026
- **Also known as:** GHSA-f3r7-pgvq-gjh2

## What is CVE-2011-10029?

CVE-2011-10029 is a high-severity denial of service vulnerability in Flexbyte Software Solar FTP Server, published on 20 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Solar FTP Server fails to properly handle format strings passed to the USER command. When a specially crafted string containing format specifiers is sent, the server crashes due to a read access violation in the __output_1() function of sfsservice.exe. This results in a denial of service (DoS) condition.

Weakness: CWE-134 (Use of Externally-Controlled Format String)

## Which versions are affected by CVE-2011-10029?


## How do I fix CVE-2011-10029?

No fix has been published for CVE-2011-10029 yet. Limit exposure of the affected software until one is available.

## Is CVE-2011-10029 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2011-10029 exists.

Public exploit code:

- Solar FTP Server Malformed USER Denial of Service (metasploit)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-10029 and fix it if it is affected.

What it is: CVE-2011-10029 is a high-severity denial of service vulnerability in Flexbyte Software Solar FTP Server, published on 20 Aug 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-2011-10029 exists.

Affected product: Flexbyte Software Solar FTP Server. 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-2011-10029/ (Markdown: https://insights.sbomify.com/CVE-2011-10029/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-10029
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-10029
- OSV: https://osv.dev/vulnerability/CVE-2011-10029

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-10029/
Summaries are generated and may contain mistakes; the official description above is the record.