Vulnerability-Lookup

CVE-2026-90982 (GCVE-0-2026-90982)

Vulnerability from cvelistv5 – Published: 2026-09-17 06:55 – Updated: 2026-09-17 06:55

Title

@fastify/static vulnerable to route guard bypass via path case-folding

Summary

@fastify/static is a Fastify plugin that serves static files from a configured root directory. In versions before 10.1.4, on a case-insensitive filesystem such as Windows or the default macOS volume, a route guard or allowedPath restriction can be bypassed by altering the letter case of a path segment. The route matcher is case-sensitive while the filesystem is not, so a request that changes the case of a protected segment does not match the guarded route and falls through to the static handler, yet the filesystem resolves it to the same protected file. As a result, an unauthenticated request can read a file that a route guard or allowedPath was configured to protect. The issue does not affect case-sensitive filesystems and is not a directory traversal, since nothing is served from outside the configured root. The issue is fixed in @fastify/static 10.1.4, which validates the requested path against its actual on-disk spelling and rejects case-aliased paths before authorization. As a workaround, serve static files from a case-sensitive filesystem, or ensure route guards and allowedPath rules account for every letter-case variant of the protected paths.

Severity

5.3 (Medium)


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

CWE

CWE-178 - Improper Handling of Case Sensitivity
CWE-284 - Improper Access Control

Assigner

openjs redhat root

References

2 references

URL	Tags
https://github.com/fastify/fastify-static/securit…
https://cna.openjsf.org/security-advisories.html

Impacted products

1 product

Vendor	Product	Version	CPE status
@fastify/static	@fastify/static	Affected: 0 , < 10.1.4 (semver) Unaffected: 10.1.4 (semver)	guessed

Credits

0xRenSec mcollina UlisesGascon

Show details on NVD website

JSON

To clipboard

{
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      "credits": [
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          "value": "0xRenSec"
        },
        {
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          "type": "remediation developer",
          "value": "mcollina"
        },
        {
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          "type": "remediation reviewer",
          "value": "UlisesGascon"
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              "value": "@fastify/static is a Fastify plugin that serves static files from a configured root directory. In versions before 10.1.4, on a case-insensitive filesystem such as Windows or the default macOS volume, a route guard or allowedPath restriction can be bypassed by altering the letter case of a path segment. The route matcher is case-sensitive while the filesystem is not, so a request that changes the case of a protected segment does not match the guarded route and falls through to the static handler, yet the filesystem resolves it to the same protected file. As a result, an unauthenticated request can read a file that a route guard or allowedPath was configured to protect. The issue does not affect case-sensitive filesystems and is not a directory traversal, since nothing is served from outside the configured root. The issue is fixed in @fastify/static 10.1.4, which validates the requested path against its actual on-disk spelling and rejects case-aliased paths before authorization. As a workaround, serve static files from a case-sensitive filesystem, or ensure route guards and allowedPath rules account for every letter-case variant of the protected paths."
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    "cveId": "CVE-2026-90982",
    "datePublished": "2026-09-17T06:55:42.300Z",
    "dateReserved": "2026-09-14T13:46:58.766Z",
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  }
}

FKIE_CVE-2026-90982

Vulnerability from fkie_nvd - Published: 2026-09-17 07:16 - Updated: 2026-09-17 07:16

Severity

5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Summary

References

	URL	Tags
	ce714d77-add3-4f53-aff5-83d477b104bb	https://cna.openjsf.org/security-advisories.html
	ce714d77-add3-4f53-aff5-83d477b104bb	https://github.com/fastify/fastify-static/security/advisories/GHSA-r799-r9gc-m956

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
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    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/@fastify/static",
          "product": "@fastify/static",
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              "version": "0",
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            },
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              "version": "10.1.4",
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    }
  ],
  "id": "CVE-2026-90982",
  "lastModified": "2026-09-17T07:16:28.647",
  "metrics": {
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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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.