@fastify/static vulnerable to route guard bypass via path traversal

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• fastify fastify-staticbefore 10.1.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (openjs). Independent of NVD's CPE analysis and usually ahead of it.

• @fastify/static @fastify/static

  • 10.1.1not affected
  • before 10.1.1affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2021-22964A redirect vulnerability in the `fastify-static` module version >= 4.2.4 and < 4.4.1 allows remote attackers to redirect Mozilla Firefox use
  35Monitor
• CVE-2026-18427@fastify/static vulnerable to route guard bypass via non-canonical path segments
  30Monitor
• CVE-2021-22963A redirect vulnerability in the fastify-static module version < 4.2.4 allows remote attackers to redirect users to arbitrary websites via a
  24Monitor
• CVE-2026-6414@fastify/static vulnerable to route guard bypass via encoded path separators
  23Monitor
• CVE-2026-7120@fastify/static vulnerable to Authorization Bypass via Non-Canonical URL Paths
  21Monitor
• CVE-2026-6410@fastify/static vulnerable to path traversal in directory listing
  21Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const file = path.join(ROOT, req.query.name);2res.sendFile(file);

1const file = path.resolve(ROOT, req.query.name);2if (!file.startsWith(ROOT + path.sep)) {3  return res.sendStatus(400);4}5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.