How to fix or mitigate CVE-2025-55209?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

CVE-2025-55209

Q: What is the CVSS score of CVE-2025-55209?

CVE-2025-55209 has a CVSS 4.0 base score of 5.1 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2025-09-04 security-advisories@github.com

Privilege Escalation XSS

5.1

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

5.1 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:10 vuln.today

CVE Published

Sep 04, 2025 - 23:15 nvd

MEDIUM 5.1

DescriptionGitHub Advisory

contactmanager is a module for FreePBX@, which is an open source GUI that controls and manages Asterisk© (PBX). In versions 15.0.14 and below, 16.0.0 through 16.0.26.4 and 17.0.0 through 17.0.5, a stored cross-site scripting (XSS) vulnerability in FreePBX allows a low-privileged User Control Panel (UCP) user to inject malicious JavaScript into the system. The malicious code executes in the context of an administrator when they interact with the affected component, leading to session hijacking and potential privilege escalation. This issue is fixed in versions 15.0.14, 16.0.27 and 17.0.6.

AnalysisAI

contactmanager is a module for FreePBX@, which is an open source GUI that controls and manages Asterisk© (PBX). Rated medium severity (CVSS 5.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

Technical ContextAI

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. contactmanager is a module for FreePBX@, which is an open source GUI that controls and manages Asterisk© (PBX). In versions 15.0.14 and below, 16.0.0 through 16.0.26.4 and 17.0.0 through 17.0.5, a stored cross-site scripting (XSS) vulnerability in FreePBX allows a low-privileged User Control Panel (UCP) user to inject malicious JavaScript into the system. The malicious code executes in the context of an administrator when they interact with the affected component, leading to session hijacking and potential privilege escalation. This issue is fixed in versions 15.0.14, 16.0.27 and 17.0.6. Version information: through 16.0.26.4.

Affected ProductsAI

See vendor advisory for affected versions.

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.