# CVE-2026-57496: NetLicensing MCP Server: REST Path Traversal Bypasses Token Redaction

> Path traversal allows authenticated users to bypass token redaction and retrieve plaintext API keys, potentially leading to full account compromise.

- **Severity:** Critical 9.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-hxpf-9xvq-wph8, PYSEC-2026-3489

## What is CVE-2026-57496?

CVE-2026-57496 is a critical path traversal vulnerability in Labs64 NetLicensing-MCP, published on 15 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

NetLicensing MCP Server is a natural-language interface that enables agentic applications to manage the software-licensing lifecycle in Labs64 NetLicensing. Prior to 0.1.8, netlicensing_get_product passes the caller-controlled product_number to src/netlicensing_mcp/tools/products.py, which interpolates it into a REST path consumed by nl_get() in src/netlicensing_mcp/client.py without path-segment validation. A traversal segment can be normalized from the intended product path to the /token endpoint, after which the response is serialized through _wrap_json instead of _wrap_json_token_read, bypassing redact_token_read() protections for APIKEY number and SHOP shopURL fields. An authenticated MCP client with a non-administrative API key can retrieve plaintext token values, and a recovered administrative token can provide broad read, write, and delete access to the NetLicensing account. This issue is fixed in version 0.1.8.

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

## Which versions are affected by CVE-2026-57496?

3 open source packages ship an affected version, including netlicensing-mcp.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `netlicensing-mcp` | PyPI | All versions | 0.1.8 |
| `netlicensing-mcp` | PyPI | All versions | 0.1.8 |
| `netlicensing-mcp` | PyPI | All versions | 0.1.8 |

## How do I fix CVE-2026-57496?

Upgrade netlicensing-mcp to 0.1.8 or later.

## Is CVE-2026-57496 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-57496 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57496 and fix it if it is affected.

What it is: CVE-2026-57496 is a critical path traversal vulnerability in Labs64 NetLicensing-MCP, published on 15 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-57496 exists.

Affected packages and fixed versions:
- netlicensing-mcp (PyPI): affected all versions; fixed in 0.1.8
- netlicensing-mcp (PyPI): affected all versions; fixed in 0.1.8
- netlicensing-mcp (PyPI): affected all versions; fixed in 0.1.8

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-2026-57496/ (Markdown: https://insights.sbomify.com/CVE-2026-57496/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57496
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57496
- OSV: https://osv.dev/vulnerability/CVE-2026-57496

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-57496/
Summaries are generated and may contain mistakes; the official description above is the record.