# CVE-2026-15074: @fastify/static vulnerable to route guard bypass via path traversal

> An unauthenticated attacker can bypass route guards to read files within the static root directory using dot-dot path segments.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Jul 2026
- **Updated:** 23 Jul 2026
- **Also known as:** GHSA-83w8-p2f5-377r, MINI-p3xf-68hm-jf7r

## What is CVE-2026-15074?

CVE-2026-15074 is a high-severity path traversal vulnerability in @fastify/static, published on 23 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-15074?

2 open source packages ship an affected version, including @fastify/static. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@fastify/static` | npm | All versions | 10.1.1 |
| `@fastify/static` | npm | All versions | 10.1.1 |

Products: Fastify Fastify-Static.

## How do I fix CVE-2026-15074?

Upgrade @fastify/static to 10.1.1 or later.

## Is CVE-2026-15074 being exploited?

There is no known exploitation of CVE-2026-15074 in the wild and no public exploit code.

## Other vulnerabilities in @fastify/static

- [CVE-2021-22964](https://insights.sbomify.com/CVE-2021-22964/): DOS and Open Redirect with user input (high 8.8)
- [CVE-2026-18427](https://insights.sbomify.com/CVE-2026-18427/): @fastify/static vulnerable to route guard bypass via non-canonical path segments (high 7.5)
- [CVE-2021-22963](https://insights.sbomify.com/CVE-2021-22963/): URL Redirection to Untrusted Site ('Open Redirect') in fastify-static (medium 6.1)
- [CVE-2026-6414](https://insights.sbomify.com/CVE-2026-6414/): @fastify/static vulnerable to route guard bypass via encoded path separators (medium 5.9)
- [CVE-2026-7120](https://insights.sbomify.com/CVE-2026-7120/): @fastify/static vulnerable to Authorization Bypass via Non-Canonical URL Paths (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15074 and fix it if it is affected.

What it is: CVE-2026-15074 is a high-severity path traversal vulnerability in @fastify/static, published on 23 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-15074 in the wild and no public exploit code.

Affected packages and fixed versions:
- @fastify/static (npm): affected all versions; fixed in 10.1.1
- @fastify/static (npm): affected all versions; fixed in 10.1.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-15074/ (Markdown: https://insights.sbomify.com/CVE-2026-15074/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15074
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15074
- OSV: https://osv.dev/vulnerability/CVE-2026-15074

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-15074/
Summaries are generated and may contain mistakes; the official description above is the record.