CVE-2026-15074

@fastify/static vulnerable to route guard bypass via path traversal

HIGH
7.5
CVSS Score
Published: July 23, 2026 at 03:01 AM UTC
Updated: July 28, 2026 at 05:15 PM UTC
2 products affected across 2 vendorsFastify Static@fastify/static

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Severity
HIGH7.5
Exploit prediction
EPSS 0.7%
SSVC
No known exploit

Description

@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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 10.1.1
Affected range stops below 10.1.1, so it looks safe — our inference, not a vendor statement
v < 10.1.1
Vendor states this is fixed in 10.1.1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHopenjs
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22

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