What is the CVSS score of CVE-2020-5216?

CVE-2020-5216 has a CVSS 3.1 base score of 5.8 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N. EPSS exploitation probability: 1.1%.

Is there a public PoC exploit available for CVE-2020-5216?

Yes, a public proof-of-concept exploit is available for CVE-2020-5216. Prioritise patching immediately. EPSS: 1.1%.

Is there a patch available for CVE-2020-5216?

Yes, a patch is available for CVE-2020-5216. Update the affected software to the latest version immediately.

Secure Headers CVE-2020-5216

MEDIUM

HTTP Response Splitting (CWE-113)

2020-01-23 security-advisories@github.com

Code Injection Twitter Secure Headers

5.8

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-113 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization HTTP response header sanitization
Impact	CVSS score of 5.8 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 1.1% exploitation probability (EPSS)

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AnalysisAI

In Secure Headers (RubyGem secure_headers), a directive injection vulnerability is present in versions before 3.9.0, 5.2.0, and 6.3.0. Rated medium severity (CVSS 5.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affected Packages

rubygems secure_headers fix: 3.9.0, 5.2.0, 6.3.0

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 under CWE-113. In Secure Headers (RubyGem secure_headers), a directive injection vulnerability is present in versions before 3.9.0, 5.2.0, and 6.3.0. If user-supplied input was passed into append/override_content_security_policy_directives, a newline could be injected leading to limited header injection. Upon seeing a newline in the header, rails will silently create a new Content-Security-Policy header with the remaining value of the original string. It will continue to create new headers for each newline. This has been fixed in 6.3.0, 5.2.0, and 3.9.0. Affected products include: Twitter Secure Headers. Version information: before 3.9.0.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.8 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

Low

Availability

None

DescriptionNVD

In Secure Headers (RubyGem secure_headers), a directive injection vulnerability is present in versions before 3.9.0, 5.2.0, and 6.3.0. If user-supplied input was passed into append/override_content_security_policy_directives, a newline could be injected leading to limited header injection. Upon seeing a newline in the header, rails will silently create a new Content-Security-Policy header with the remaining value of the original string. It will continue to create new headers for each newline. This has been fixed in 6.3.0, 5.2.0, and 3.9.0.

Threat Intelligence Overview

EPSS Score

1.1%

Top 39% exploitable

Exploit

POC

Public exploit code exists

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

GitHub

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.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC Yes

EPSS 1.1%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +29

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.