CVE-2026-28298: SolarWinds Observability XSS Vulnerability

CVE-2026-28298 Overview

SolarWinds Observability Self-Hosted was found to be affected by a stored cross-site scripting (XSS) vulnerability, which when exploited, can lead to unintended script execution. This vulnerability allows attackers with high privileges on an adjacent network to inject malicious scripts that persist in the application and execute when other users access the affected content.

Critical Impact

Successful exploitation could lead to unauthorized access to sensitive data, session hijacking, and potential compromise of user credentials within the SolarWinds Observability environment.

Affected Products

• SolarWinds Observability Self-Hosted (versions prior to 2026.1.1)

Discovery Timeline

• 2026-03-26 - CVE-2026-28298 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-28298

Vulnerability Analysis

This stored cross-site scripting (XSS) vulnerability (CWE-79) affects SolarWinds Observability Self-Hosted. The attack requires the attacker to be on an adjacent network and possess high-level privileges within the application. User interaction is required for successful exploitation, meaning a victim must view the page containing the malicious script.

The vulnerability enables attackers to store malicious JavaScript code within the application's database or storage layer. When legitimate users subsequently access pages that render this stored content, the malicious scripts execute within their browser context. This can result in high impact to both confidentiality and integrity, as attackers can potentially steal session tokens, modify displayed content, or perform actions on behalf of the victim user.

Root Cause

The root cause of this vulnerability is insufficient input sanitization and output encoding within the SolarWinds Observability Self-Hosted application. User-supplied input is stored without proper validation and subsequently rendered to other users without adequate encoding, allowing embedded script content to execute in the victim's browser context.

Attack Vector

The attack vector requires adjacency to the target network and elevated privileges within the SolarWinds Observability application. An authenticated attacker with high-level permissions can inject malicious script payloads into input fields or data storage areas that are later displayed to other users. The stored nature of this XSS variant means the malicious payload persists across sessions and can affect multiple users who view the compromised content.

The vulnerability manifests in areas where user input is stored and later rendered without proper sanitization. See the SolarWinds Security Advisory for technical details and specific affected components.

Detection Methods for CVE-2026-28298

Indicators of Compromise

• Unusual JavaScript execution patterns in browser developer tools when accessing SolarWinds Observability pages
• Unexpected outbound network requests from the SolarWinds web interface to unknown domains
• Modified or suspicious content appearing in stored data fields that may contain script tags or event handlers
• User reports of unexpected browser behavior or pop-ups when using the Observability interface

Detection Strategies

• Review web application logs for suspicious input patterns containing script tags, event handlers, or encoded JavaScript
• Implement Content Security Policy (CSP) headers to detect and report script injection attempts
• Monitor for unusual authentication or session activity that could indicate session token theft
• Conduct periodic code reviews and security scans of stored content for XSS payloads

Monitoring Recommendations

• Enable verbose logging for the SolarWinds Observability Self-Hosted application
• Configure web application firewalls (WAF) to detect and alert on XSS patterns
• Monitor user session activity for anomalies that could indicate compromise
• Set up alerts for multiple failed or unusual authentication attempts following XSS-like activity

How to Mitigate CVE-2026-28298

Immediate Actions Required

• Update SolarWinds Observability Self-Hosted to version 2026.1.1 or later as documented in the release notes
• Audit recent changes to stored data for suspicious script content
• Review privileged user activity logs for signs of malicious input injection
• Implement Content Security Policy headers to mitigate script execution risks

Patch Information

SolarWinds has released a security update addressing this vulnerability. Organizations should upgrade to SolarWinds Observability Self-Hosted version 2026.1.1 or later. Detailed patch information is available in the SolarWinds Orion Release Notes and the SolarWinds Security Advisory for CVE-2026-28298.

Workarounds

• Restrict network access to the SolarWinds Observability interface to trusted segments only
• Limit the number of users with high-level administrative privileges
• Implement strict Content Security Policy (CSP) headers to prevent inline script execution
• Consider using a web application firewall (WAF) with XSS filtering capabilities as an additional layer of defense

# Example CSP header configuration for Apache
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'self';"