CVE-2026-15074: @fastify/static up to and including version 10.1.0 fails to reject dot-dot path segments in request pathnames before the file-resolution stage. This is a bypass of the earlier fix

highCVSS 7.5CVE-2026-15074

@fastify/static up to and including version 10.1.0 fails to reject dot-dot path segments in request pathnames before the file-resolution stage. This is a bypass of the earlier fix for CVE-2026-6414, which only covered encoded forward slashes. Because the underlying send library normalizes dot segments before applying its own path-traversal guard, an unauthenticated attacker can bypass any route-scoped middleware and read files inside the static root that live under the guarded URL prefix. The bypass does not allow access outside the configured static root by itself, it defeats route-guard filtering only. The issue is patched in @fastify/static 10.1.1.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.5
Published: 2026-07-23
Last updated: 2026-07-28
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-15074

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.

highGHSA-83w8-p2f5-377r: @fastify/static vulnerable to route guard bypass via path traversalghsa

Recent advisories for @fastify/static

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumGHSA-8pvw-jcv7-9cmj: @fastify/static vulnerable to Authorization Bypass via Non-Canonical URL Pathsghsa · 2026-07-24
highGHSA-83w8-p2f5-377r: @fastify/static vulnerable to route guard bypass via path traversalghsa · 2026-07-24
mediumCVE-2026-7120: @fastify/static evaluates the allowedPath callback before normalizing dot segments and duplicat…nvd · 2026-07-23