Rack
CVE-2018-16471
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 6.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. |
| Exploit ScenarioDerived | A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in rubygems
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Carefully crafted requests can impact the data returned by the scheme method on Rack::Request. Applications that expect the scheme to be limited to 'http' or 'https' and do not escape the return value could be vulnerable to an XSS attack. Note that applications using the normal escaping mechanisms provided by Rails may not impacted, but applications that bypass the escaping mechanisms, or do not use them may be vulnerable. Affected products include: Rack Project Rack, Debian Debian Linux. Version information: before 2.0.6.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Carefully crafted requests can impact the data returned by the scheme method on Rack::Request. Applications that expect the scheme to be limited to 'http' or 'https' and do not escape the return value could be vulnerable to an XSS attack. Note that applications using the normal escaping mechanisms provided by Rails may not impacted, but applications that bypass the escaping mechanisms, or do not use them may be vulnerable.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
Affected Products (CPE)NVD
Directory traversal in Rack versions prior to 2.2.22, 3.1.20, and 3.2.5 allows unauthenticated remote attackers to list
Rack is a modular Ruby web server interface. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable,
Rack is a modular Ruby web server interface. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable,
A reliance on cookies without validation/integrity check security vulnerability exists in rack < 2.2.3, rack < 2.1.4 tha
A sequence injection vulnerability exists in Rack <2.0.9.1, <2.1.4.1 and <2.2.3.1 which could allow is a possible shell
Rack provides an interface for developing web applications in Ruby. Rated medium severity (CVSS 5.7), this vulnerability
Rack's Directory module fails to sanitize filenames when generating HTML directory listings, allowing attackers to craft
Session authentication bypass in Rack::Session::Cookie 2.0.0 through 2.1.1 allows unauthenticated remote attackers to fo
A directory traversal vulnerability exists in rack < 2.2.0 that allows an attacker perform directory traversal vulnerabi
Rack::Session::Cookie in Rack 1.5.x before 1.5.2, 1.4.x before 1.4.5, 1.3.x before 1.3.10, 1.2.x before 1.2.8, and 1.1.x
A DoS vulnerability exists in Rack <v3.0.4.2, <v2.2.6.3, <v2.1.4.3 and <v2.0.9.3 within in the Multipart MIME parsing co
Memory exhaustion denial of service in the Ruby Rack web server interface (versions prior to 2.2.19, 3.1.17, and 3.2.2)
GitHub PoC
Exploit-DB