CVE intelligence and bounded remediation

CVE-2026-30942 — Flare is a Next.js-based, self-hostable file sharing platform that integrates with screenshot tools

High CVSS 8.3

Flare is a Next.js-based, self-hostable file sharing platform that integrates with screenshot tools. Prior to 1.7.3, an authenticated path traversal vulnerability in /api/avatars/[filename] allows any logged-in user to read arbitrary files from within the application container. The filename URL parameter is passed to path.join() without sanitization, and getFileStream() performs no path validation, enabling %2F-encoded ../ sequences to escape the uploads/avatars/ directory and read any file accessible to the nextjs process under /app/. Authentication is enforced by Next.js middleware. However, on instances with open registration enabled (the default), any attacker can self-register and immediately exploit this. This vulnerability is fixed in 1.7.3.

Severity
High
CVSS
8.3 (4.0)
Published
2026-03-10
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

  • flintsh / flare

Matched remediation archetype

Path traversal, unsafe upload, and file handling

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Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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