CVE-2026-90982

@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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://cna.openjsf.org/security-advisories.html
https://github.com/fastify/fastify-static/security/advisories/GHSA-r799-r9gc-m956

Configurations

No configuration.

History

17 Sep 2026, 07:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-17 07:16

Updated : 2026-09-18 19:07

NVD link : CVE-2026-90982

Mitre link : CVE-2026-90982

CVE.ORG link : CVE-2026-90982

JSON object : View

Products Affected

No product.

CWE

CWE-178

Improper Handling of Case Sensitivity

CWE-284

Improper Access Control

{"id": "CVE-2026-90982", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-90982", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-17T12:32:46.853799Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 3.9}]}, "affected": [{"source": "ce714d77-add3-4f53-aff5-83d477b104bb", "affectedData": [{"vendor": "@fastify/static", "product": "@fastify/static", "versions": [{"status": "affected", "version": "0", "lessThan": "10.1.4", "versionType": "semver"}, {"status": "unaffected", "version": "10.1.4", "versionType": "semver"}], "packageURL": "pkg:npm/@fastify/static", "defaultStatus": "unaffected"}]}], "published": "2026-09-17T07:16:28.647", "references": [{"url": "https://cna.openjsf.org/security-advisories.html", "source": "ce714d77-add3-4f53-aff5-83d477b104bb"}, {"url": "https://github.com/fastify/fastify-static/security/advisories/GHSA-r799-r9gc-m956", "source": "ce714d77-add3-4f53-aff5-83d477b104bb"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "description": [{"lang": "en", "value": "CWE-178"}, {"lang": "en", "value": "CWE-284"}]}], "descriptions": [{"lang": "en", "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."}], "lastModified": "2026-09-18T19:07:38.320", "sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb"}