CVE-2025-49007

MEDIUM

ReDoS Vulnerability in Rack::Multipart handle_mime_head

Published June 5, 2025Updated February 4, 2026Source: osv

Summary

### Summary There is a denial of service vulnerability in the Content-Disposition parsing component of Rack. This is very similar to the previous security issue CVE-2022-44571. ### Details Carefully crafted input can cause Content-Disposition header parsing in Rack to take an unexpected amount of time, possibly resulting in a denial of service attack vector. This header is used typically used in multipart parsing. Any applications that parse multipart posts using Rack (virtually all Rails applications) are impacted. ### Credits Thanks to [scyoon](https://hackerone.com/scyoon) for reporting this to the Rails security team

Remediation

Upgrade to the fixed version using your package manager.

Bundler

Update rack to 3.1.16 or later

gem install rack -v 3.1.16

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (1)

Package	Ecosystem	Affected	Fixed In
rack	rubygems	3.1.0, 3.1.1, 3.1.10, 3.1.11 (+12 more)	3.1.16

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CWE-770
Allocation of Resources Without LimitsMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 7.5 score means for each attack dimension.

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

—

Confidentiality

—

Integrity

—

Availability

—

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/E:U

References

Frequently Asked Questions

What is CVE-2025-49007?: ReDoS Vulnerability in Rack::Multipart handle_mime_head This vulnerability has been assigned a severity rating of MEDIUM (CVSS score: 7.5/10).
How do I check if my project is affected by CVE-2025-49007?: CVE-2025-49007 affects rack. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2025-49007 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score

7.5

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-47m2-26rw-j2jw

Related CVEs

CVE-2023-27530
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Rack has possible DoS Vulnerability in Multipart MIME parsing
CVE-2020-8161
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Rack has an unsafe default in Rack::QueryParser allows params_limit bypass via semicolon-separated parameters
CVE-2022-44570
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Denial of service via header parsing in Rack
CVE-2025-61919
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Rack is vulnerable to a memory-exhaustion DoS through unbounded URL-encoded body parsing
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CVE-2026-34763
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Rack has a root directory disclosure via unescaped regex interpolation in Rack::Directory
CVE-2025-27111
MEDIUM
Escape Sequence Injection vulnerability in Rack lead to Possible Log Injection

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