CVE-2026-90982 (GCVE-0-2026-90982)
Vulnerability from cvelistv5 – Published: 2026-09-17 06:55 – Updated: 2026-09-17 12:33
VLAI
EPSS
VEX
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)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-17 12:32 UTC
Assigner
References
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 |
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