GHSA-83w8-p2f5-377r: @fastify/static vulnerable to route guard bypass via path traversal
Impact
@fastify/static is vulnerable to a bypass of route-based middleware and guards via non-leading .. and %2E%2E path segments. find-my-way does not normalize .. when matching routes, so a request such as /foo/../deep/secret.txt matches the static plugin's catch-all instead of the guarded /deep/*. The getPathnameForSend helper introduced by the fix for GHSA-x428-ghpx-8j92 only guards against the %2F variant; .. and %2E%2E survive the decodeURI + encodeURI round-trip and are then collapsed away by @fastify/send's path.normalize before its own traversal guard runs.
Applications that rely on route-based middleware or guards to protect files served by @fastify/static can be bypassed with non-leading dot-dot path segments.
Patches
Upgrade to @fastify/static 10.1.1.
Workarounds
Do not use route-based middlewares or guards to protect files served by @fastify/static.
Details
Original advisory: https://github.com/advisories/GHSA-83w8-p2f5-377r
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-150740.45% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 37% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-15074 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
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