CVE-2026-26993: Flare has XSS vulnerability in Raw File Preview

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-02-20 · updated 2026-06-17
Weakness: CWE-79

Description

Flare is a Next.js-based, self-hostable file sharing platform that integrates with screenshot tools. Versions 1.7.0 and below allow users to upload files without proper content validation or sanitization. By embedding malicious JavaScript within an SVG (or other active content formats such as HTML or XML), an attacker can achieve script execution in the context of the application's origin when a victim views the file in “raw” mode. This results in a stored Cross-Site Scripting (XSS) vulnerability that can be exploited to exfiltrate user data. This issue has been fixed in version 1.7.1.

Affected products

FlintSH Flare: before 1.7.1 — fixed in 1.7.1

How to fix

Upgrade to a fixed version: FlintSH Flare 1.7.1. Check the vendor advisory for mitigations.

References

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