CVE-2026-6414
@fastify/static vulnerable to route guard bypass via encoded path separators
- State
- Published
- Severity
- 5.9 Medium
- Published
- Apr 16, 2026
- Updated
- Apr 16, 2026
- Reserved
- Apr 15, 2026
Description
@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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | openjs |
Weaknesses
- CWE-177 Improper Handling of URL Encoding (Hex Encoding)
Affected Products
| Product | Versions |
|---|---|
@fastify/static@fastify/static |
|
References
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