CVE-2026-6414@fastify/static vulnerable to route guard bypass via encoded path separators
- 5.9MediumCVSS base score
- 0.43%Exploitation in 30 daysEPSS · top 62% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By openjs
- 1 day later
· 1 day later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| openjsCNA (assigner) | 3.1 | Medium5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| NVDNVD · Analyzed | 3.1 | Medium5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.43% · top 62% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.
Affected products
@fastify/static · @fastify/static
- affected 8.0.0 – < 9.1.1
- unaffected 9.1.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npm@fastify/staticGHSA-x428-ghpx-8j92 (opens in a new tab)
References
References4
- https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p (opens in a new tab)
- https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwr (opens in a new tab)
- https://github.com/fastify/fastify-static/security/advisories/GHSA-x428-ghpx-8j92 (opens in a new tab)
- https://cna.openjsf.org/security-advisories.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-23227 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-x428-ghpx-8j92 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-6414)Record last updated .