# CVE-2026-90869: Pre-Authentication SSH Denial of Service via Malformed Public-Key Signature in Progress WS_FTP Server


- **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
- **Fix available:** No
- **Published:** 29 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-47x4-grc2-rh4m

## What is CVE-2026-90869?

CVE-2026-90869 is a high-severity vulnerability in Progress Software WS_FTP Server, published on 29 Oct 2026. 

### Official description

A remote attacker who knows a valid account's enrolled SSH public key can terminate the shared SSH service in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows.

Weakness: CWE-20 (Improper Input Validation), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-90869?


## How do I fix CVE-2026-90869?

No fix has been published for CVE-2026-90869 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90869 being exploited?

There is no known exploitation of CVE-2026-90869 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90869 and fix it if it is affected.

What it is: CVE-2026-90869 is a high-severity vulnerability in Progress Software WS_FTP Server, published on 29 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-90869 in the wild and no public exploit code.

Affected product: Progress Software WS_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-2026-90869/ (Markdown: https://insights.sbomify.com/CVE-2026-90869/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90869
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90869
- OSV: https://osv.dev/vulnerability/CVE-2026-90869

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90869/
Summaries are generated and may contain mistakes; the official description above is the record.