# CVE-2026-63188: logto-tunnel serves files outside --experience-path via path traversal

> An unauthenticated attacker can read arbitrary files outside the static directory via path traversal in the Logto tunnel package when experience-path is enabled.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** GHSA-rxjr-6c9q-h67x, MINI-43c2-qm78-m77j, MINI-62xh-2fmg-xhvx

## What is CVE-2026-63188?

CVE-2026-63188 is a high-severity path traversal vulnerability in logto-io logto, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 0.3.9, the Logto Tunnel npm package enabled createStaticFileProxy from packages/tunnel/src/commands/tunnel/index.ts and passed request.url from static asset requests through packages/tunnel/src/commands/tunnel/utils.ts using path.join(staticPath, request.url) and then fs.open(requestPath, "r") without URL normalization or a containment check. When --experience-path was enabled and the tunnel port was reachable, an unauthenticated requester could send a path containing ../ to createStaticFileProxy and read files outside the configured static directory that were readable by the logto-tunnel process. The service used server.listen(port), which could expose the tunnel to other hosts depending on the platform and deployment. This issue is fixed in version 0.3.9.

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

## Which versions are affected by CVE-2026-63188?

2 open source packages ship an affected version, including @logto/tunnel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@logto/tunnel` | npm | All versions | 0.3.9 |
| `@logto/tunnel` | npm | All versions | 0.3.9 |

## How do I fix CVE-2026-63188?

Upgrade @logto/tunnel to 0.3.9 or later.

## Is CVE-2026-63188 being exploited?

There is no known exploitation of CVE-2026-63188 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63188 and fix it if it is affected.

What it is: CVE-2026-63188 is a high-severity path traversal vulnerability in logto-io logto, published on 19 Aug 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-2026-63188 in the wild and no public exploit code.

Affected packages and fixed versions:
- @logto/tunnel (npm): affected all versions; fixed in 0.3.9
- @logto/tunnel (npm): affected all versions; fixed in 0.3.9

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-2026-63188/ (Markdown: https://insights.sbomify.com/CVE-2026-63188/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63188
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63188
- OSV: https://osv.dev/vulnerability/CVE-2026-63188

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63188/
Summaries are generated and may contain mistakes; the official description above is the record.