Rack up to 2.2.18/3.1.16/3.2.1 Multipart Form Rack::Multipart::Parser resource consumption

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Rack up to 2.2.18/3.1.16/3.2.1. Affected by this issue is the function Rack::Multipart::Parser of the component Multipart Form Handler. Performing a manipulation results in resource consumption. This vulnerability is known as CVE-2025-61771. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Rack up to 2.2.18/3.1.16/3.2.1. This affects the function Rack::Multipart::Parser of the component Multipart Form Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2025-61771 since 09/30/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 269982 (Ruby Rack < 2.2.19 / 3.1.x < 3.1.17 / 3.2.x < 3.2.2 Multiple Vulnerabilities), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.2.19, 3.1.17 or 3.2.2 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (269982) and CERT Bund (WID-SEC-2025-2482). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Debian Linux
• Red Hat Enterprise Linux
• Oracle Linux
• RESF Rocky Linux

Productinfo

Name

• Rack

Version

• 2.2.0
• 2.2.1
• 2.2.2
• 2.2.3
• 2.2.4
• 2.2.5
• 2.2.6
• 2.2.7
• 2.2.8
• 2.2.9
• 2.2.10
• 2.2.11
• 2.2.12
• 2.2.13
• 2.2.14
• 2.2.15
• 2.2.16
• 2.2.17
• 2.2.18
• 3.1.0
• 3.1.1
• 3.1.2
• 3.1.3
• 3.1.4
• 3.1.5
• 3.1.6
• 3.1.7
• 3.1.8
• 3.1.9
• 3.1.10
• 3.1.11
• 3.1.12
• 3.1.13
• 3.1.14
• 3.1.15
• 3.1.16
• 3.2.0
• 3.2.1

Website

• Product: https://github.com/rack/rack/

CPE 2.3info

• 🔒
• 🔒
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CPE 2.2info

• 🔒
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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 269982
Nessus Name: Ruby Rack < 2.2.19 / 3.1.x < 3.1.17 / 3.2.x < 3.2.2 Multiple Vulnerabilities

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Rack 2.2.19/3.1.17/3.2.2

Timelineinfo

09/30/2025 CVE reserved
10/07/2025 +7 days Advisory disclosed
10/07/2025 +0 days VulDB entry created
11/05/2025 +29 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2025-61771 (🔒)
GCVE (CVE): GCVE-0-2025-61771
GCVE (VulDB): GCVE-100-327405
CERT Bund: WID-SEC-2025-2482 - Red Hat Enterprise Linux: Mehrere Schwachstellen erm&ouml;glichen Denial of Service

Entryinfo

Created: 10/07/2025 17:00
Updated: 11/05/2025 16:37
Changes: 10/07/2025 17:00 (64), 10/11/2025 01:32 (2), 11/05/2025 16:37 (7)
Complete: 🔍
Cache ID: 216::103

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Discussion

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