Cyber Resilience

CVE-2026-15074

Path Traversal in Fastify-Static ≤ 10.1.1

Published
23 July 2026
Modified
28 July 2026
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0045 37th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-15074 is a high-severity Path Traversal (CWE-22) vulnerability in Fastify Fastify-Static. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 37th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

@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…

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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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

Path traversal in public-facing static file server directly enables exploitation of web application for unauthorized file access within root.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-6410Same product: Fastify Fastify-Static
CVE-2025-7712Shared CWE-22
CVE-2026-31802Shared CWE-22
CVE-2026-2683Shared CWE-22
CVE-2025-54453Shared CWE-22
CVE-2025-7626Shared CWE-22
CVE-2026-23633Shared CWE-22
CVE-2019-25687Shared CWE-22
CVE-2026-24953Shared CWE-22
CVE-2025-55988Shared CWE-22

Affected Assets

fastify
fastify-static
≤ 10.1.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • AC-3 Access Enforcement
  • AC-4 Information Flow Enforcement
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Mitigating Controls (NIST 800-53 r5) AI

prevent

Rejects dot-dot path segments in request pathnames before file resolution, directly blocking the path-traversal bypass.

prevent

Enforces access decisions on static routes so that route-scoped guards cannot be bypassed by unnormalized paths.

prevent

Enforces information-flow rules between URL prefixes and the static root, preventing unauthorized traversal inside the served directory.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 partial match
prevents

Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.

PR.AA-05 none match
prevents

PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development catches path traversal via static/dynamic analysis.

prevents

Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.

prevents

Application security requirements include rules for safe file handling and canonicalization.

prevents

Secure architecture principles require least-privilege file access and directory isolation.

prevents

Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.

mitigates

Information access restriction limits which files an application may read or write.

References