---
cve: "CVE-2025-61771"
severity: "HIGH"
cvss: 7.5
epss: "52%"
vendor: "rack"
kev: false
exploited: false
published: "2025-10-07 15:16:03"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T19:15:53+02:00"
---

# CVE-2025-61771

> 7.5 HIGH · 🧪 PoC

## Beschreibung

Rack is a modular Ruby web server interface. In versions prior to 2.2.19, 3.1.17, and 3.2.2, ``Rack::Multipart::Parser` stores non-file form fields (parts without a `filename`) entirely in memory as Ruby `String` objects. A single large text field in a multipart/form-data request (hundreds of megabytes or more) can consume equivalent process memory, potentially leading to out-of-memory (OOM) conditions and denial of service (DoS). Attackers can send large non-file fields to trigger excessive memory usage. Impact scales with request size and concurrency, potentially leading to worker crashes or severe garbage-collection overhead. All Rack applications processing multipart form submissions are affected. Versions 2.2.19, 3.1.17, and 3.2.2 enforce a reasonable size cap for non-file fields (e.g., 2 MiB). Workarounds include restricting maximum request body size at the web-server or proxy layer (e.g., Nginx `client_max_body_size`) and validating and rejecting unusually large form fields at the application level.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- 4c4ea296fdfd115377912aa7dbcb55b83bf2888e (Commit)
- 8d141b301dd1eeda363d87d61499fe21dd90f4a5 (Commit)

## Referenzen

- <https://github.com/rack/rack/security/advisories/GHSA-w9pc-fmgc-vxvw>
- <https://github.com/rack/rack/commit/589127f4ac8b5cf11cf88fb0cd116ffed4d2181e>
- <https://github.com/rack/rack/commit/d869fed663b113b95a74ad53e1b5cae6ab31f29e>
- <https://github.com/rack/rack/commit/e08f78c656c9394d6737c022bde087e0f33336fd>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2025-61771) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_