Vulnerability-Lookup

GHSA-X428-GHPX-8J92

Vulnerability from github – Published: 2026-04-16 22:34 – Updated: 2026-04-16 22:34

Summary

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

Details

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.

Severity

5.9 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

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JSON

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 9.1.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@fastify/static"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "9.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-6414"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-177"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T22:34:03Z",
    "nvd_published_at": "2026-04-16T13:16:52Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\n`@fastify/static` v9.1.0 and earlier decodes percent-encoded path separators (`%2F`) before filesystem resolution, but Fastify\u0027s 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.\n\nApplications that rely on route-based middleware or guards to protect files served by @fastify/static can be bypassed with encoded path separators.\n\n### Patches\n\nUpgrade to `@fastify/static` \u003e= 9.1.1.\n\n### Workarounds\n\nNone. Upgrade to the patched version.",
  "id": "GHSA-x428-ghpx-8j92",
  "modified": "2026-04-16T22:34:03Z",
  "published": "2026-04-16T22:34:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fastify-static/security/advisories/GHSA-x428-ghpx-8j92"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p"
    },
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwr"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6414"
    },
    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/fastify/fastify-static"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "@fastify/static vulnerable to route guard bypass via encoded path separators"
}

CVE-2026-6414 (GCVE-0-2026-6414)

Vulnerability from cvelistv5 – Published: 2026-04-16 13:09 – Updated: 2026-04-16 13:48

Title

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

Summary

@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.

Severity

5.9 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-16 13:48 UTC

CWE

CWE-177 - Improper Handling of URL Encoding (Hex Encoding)

Assigner

openjs redhat root Scorecard

References

4 references

URL	Tags
https://github.com/fastify/middie/security/adviso…
https://github.com/honojs/hono/security/advisorie…
https://github.com/fastify/fastify-static/securit…
https://cna.openjsf.org/security-advisories.html

Impacted products

1 product

Vendor	Product	Version
@fastify/static	@fastify/static	Affected: 8.0.0 , < 9.1.1 (semver) Unaffected: 9.1.1 (semver)

Credits

blakeembrey mcollina UlisesGascon climba03003

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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