@fastify/static vulnerable to route guard bypass via encoded path separators

TRUNG BÌNH 5.9CVE-2026-6414 · GHSA-x428-ghpx-8j92 · Công bố 16/04/2026 · cập nhật 17/06/2026

Tóm tắt nhanh

CVE-2026-6414 là lỗ hổng mức TRUNG BÌNH (CVSS 5.9) ảnh hưởng fastify-static (fastify), @fastify/static.
Xác suất bị khai thác trong 30 ngày tới (EPSS): 0.42%, cao hơn 36.5% các lỗ hổng khác.
Cách xử lý: cập nhật lên 9.1.1 hoặc mới hơn.

Gói / sản phẩm	Phiên bản bị ảnh hưởng	Phiên bản đã vá
fastify-static fastify	`≥ 8.0.0, < 9.1.1`	`9.1.1`
@fastify/static npm	`≥ 8.0.0, < 9.1.1`	`9.1.1`

Mô tả

Impact

@fastify/static v9.1.0 and earlier decodes percent-encoded path separators (%2F) before filesystem resolution, but Fastify's router treats them as literal characters. This creates a routing mismatch: route guards on /admin/* do not match /admin%2Fsecret.html, but @fastify/static decodes it to /admin/secret.html and serves the file.

Applications that rely on route-based middleware or guards to protect files served by @fastify/static can be bypassed with encoded path separators.

Patches

Upgrade to @fastify/static >= 9.1.1.

Workarounds

None. Upgrade to the patched version.

Mô tả của NVD

@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators (%2F) before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. For example, a route guard on a protected path can be circumvented by encoding the path separator in the URL. Upgrade to @fastify/static 9.1.1 to fix this issue. There are no workarounds.