Security Digest · Vulnerability record
CVE-2026-57496: netlicensing-mcp: REST Path Traversal Bypasses Token Redaction
NetLicensing MCP Server is a natural-language interface that enables agentic applications to manage the software-licensing lifecycle in Labs64 NetLicensing.
CVSS 9.6 Critical EPSS 0.4% · p28
Should you act?
Critical, preconditions apply
Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.4%, percentile 28: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 28% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes
netlicensing-mcp(PyPI) < 0.1.8, fixed in 0.1.8. Check your lockfile, including transitive dependencies.
What it is
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, netlicensinggetproduct passes the caller-controlled productnumber to src/netlicensingmcp/tools/products.py, which interpolates it into a REST path consumed by nlget() in src/netlicensingmcp/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 wrapjson instead of wrapjsontokenread, bypassing redacttokenread() 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.
From the GitHub advisory
Summary
The netlicensinggetproduct MCP tool in netlicensing-mcp interpolates a caller-controlled productnumber argument directly into a REST URL path without any validation. Passing ../token as the product number causes httpx to normalize /product/../token into /token, silently redirecting the request to the NetLicensing token endpoint instead of the intended product endpoint. The response is then serialized through the generic wrapjson wrapper rather than the token-specific wrapjsontokenread wrapper, bypassing all APIKEY number and SHOP shopURL redaction. An authenticated MCP client can recover plaintext API key values that the token read tools intentionally mask, including admin-level APIKEY credentials.
Details
The vulnerability is a path traversal (CWE-22) that exploits the interaction between unsanitized string interpolation and httpx's WHATWG URL normalization.
Source — src/netlicensingmcp/tools/products.py:22
Weakness type: CWE-22.
Product: netlicensing-mcp (PyPI) · Assigned by: GitHub_M · Published: 2026-10-15
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | netlicensing-mcp | < 0.1.8 | 0.1.8 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Labs64 | NetLicensing-MCP | < 0.1.8 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.6 Critical | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
| GitHub | 3.1 | 9.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.35% probability of exploitation activity in the next 30 days; percentile 28.
Timeline
- — GitHub-reviewed advisory GHSA-hxpf-9xvq-wph8 published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-hxpf-9xvq-wph8 github.com
- CVE.org record CVE-2026-57496 cve.org
- NVD entry CVE-2026-57496 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com