What is the CVSS score of CVE-2025-27794?

CVE-2025-27794 has a CVSS 3.1 base score of 6.8 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.2%.

How to fix or mitigate CVE-2025-27794?

Within 30 days: Identify affected systems running versions and apply vendor patches as part of regular patch cycle. Validate input sanitization for user-controlled parameters.

Flarum CVE-2025-27794

MEDIUM

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (CWE-74)

2025-03-12 security-advisories@github.com

Information Disclosure Flarum

6.8

CVSS 3.1 · GitHub Advisory

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Vulnerability Assessment

Weakness	CWE CWE-74 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Input neutralization, injection prevention
Impact	CVSS score of 6.8 (MEDIUM). Attack characteristics: network attack vector, high complexity, no privileges required, user interaction required. EPSS exploitation probability: 0.22%.
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 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Flarum is open-source forum software. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, no authentication required.

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

composer flarum/core fix: 1.8.10

composer flarum/framework fix: 1.8.10

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in composer

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-74. Flarum is open-source forum software. A session hijacking vulnerability exists in versions prior to 1.8.10 when an attacker-controlled authoritative subdomain under a parent domain (e.g., subdomain.host.com) sets cookies scoped to the parent domain (.host.com). This allows session token replacement for applications hosted on sibling subdomains (e.g., community.host.com) if session tokens aren't rotated post-authentication. Key Constraints are that the attacker must control any subdomain under the parent domain (e.g., evil.host.com or x.y.host.com), and the parent domain must not be on the Public Suffix List. Due to non-existent session token rotation after authenticating we can theoretically reproduce the vulnerability by using browser dev tools, but due to the browser's security measures this does not seem to be exploitable as described. Version 1.8.10 contains a patch for the issue. Affected products include: Flarum. Version information: prior to 1.8.10.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 6.8 MEDIUM

AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Patch released

Mar 28, 2026 - 18:31 nvd

Patch available

CVE Published

Mar 12, 2025 - 14:15 nvd

MEDIUM 6.8

DescriptionGitHub Advisory

Flarum is open-source forum software. A session hijacking vulnerability exists in versions prior to 1.8.10 when an attacker-controlled authoritative subdomain under a parent domain (e.g., subdomain.host.com) sets cookies scoped to the parent domain (.host.com). This allows session token replacement for applications hosted on sibling subdomains (e.g., community.host.com) if session tokens aren't rotated post-authentication. Key Constraints are that the attacker must control any subdomain under the parent domain (e.g., evil.host.com or x.y.host.com), and the parent domain must not be on the Public Suffix List. Due to non-existent session token rotation after authenticating we can theoretically reproduce the vulnerability by using browser dev tools, but due to the browser's security measures this does not seem to be exploitable as described. Version 1.8.10 contains a patch for the issue.

Executive ViewAI

Why It Matters

Organizations using versions should be aware of notable risk from CVE-2025-27794, a injection vulnerability rated CVSS 6.8. Exploitation could allow attackers to execute code or inject malicious input. A patch is available and should be applied during regular vulnerability management.

Business Impact: Moderate

Compensating Controls

Apply vendor patch. If patching is delayed: deploy WAF rules, restrict network access, enable logging.

Threat Intelligence Overview

EPSS Score

0.2%

Top 55% exploitable

Data Quality

4 sources

Confidence: Medium

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 No

EPSS 0.2%

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

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +34

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.