CVE-2026-30230

HighPublic PoC

Published: 06 March 2026

Published

06 March 2026

Modified

09 April 2026

KEV Added

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Patch

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CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Score 0.0002 6.3th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-30230 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Flintsh Flare. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 6.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190).

Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-24 Access Control Decisions

addresses: CWE-639

Per-request decision making makes it harder to bypass authorization using user-controlled keys without proper validation in the decision process.

AC-3 Access Enforcement

addresses: CWE-639

Consistent enforcement of approved authorizations makes bypassing via user-controlled keys ineffective.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Authorization bypass on thumbnail endpoint of public-facing Next.js web app directly enables remote unauthenticated exploitation of an Internet-facing application to access restricted file content.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

Flare is a Next.js-based, self-hostable file sharing platform that integrates with screenshot tools. Prior to version 1.7.2, the thumbnail endpoint does not validate the password for password‑protected files. It checks ownership/admin for private files but skips password verification, allowing thumbnail…

access without the password. This issue has been patched in version 1.7.2.

Deeper analysisAI

CVE-2026-30230 is an authorization bypass vulnerability (CWE-639) in Flare, a Next.js-based, self-hostable file sharing platform that integrates with screenshot tools. In versions prior to 1.7.2, the thumbnail endpoint does not validate passwords for password-protected files, despite checking ownership or admin privileges for private files. This flaw allows unauthorized access to thumbnails without the password. The vulnerability carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N) and was published on 2026-03-06T21:16:17.077.

Remote attackers require no privileges or user interaction to exploit this issue over the network. By directly accessing the thumbnail endpoint with the identifier of a password-protected file, an unauthenticated adversary can retrieve the thumbnail image, disclosing potentially sensitive visual content that was meant to be restricted by the password mechanism.

The vulnerability has been patched in Flare version 1.7.2. Additional mitigation details are available in the GitHub security advisory at https://github.com/FlintSH/Flare/security/advisories/GHSA-3x7v-x3r6-mjh7.