CVE-2026-57496 Labs64 CVE debrief

Who should care

Defenders responsible for managing the `netlicensing-mcp` package should assess exposure and prioritize remediation to prevent potential exploitation. Defenders should also review compensating controls for exposed systems while remediation is scheduled and verified. Additionally, defenders should check relevant monitoring, detection, and logs for exposed assets that need extra review.

Why it matters

This vulnerability allows an authenticated MCP client to recover plaintext API key values, including admin-level credentials, due to a path traversal vulnerability in the `netlicensing-mcp` package.

• Authenticated clients can recover plaintext API key values
• Admin-level APIKEY credentials are at risk
• Token redaction is bypassed, allowing sensitive information disclosure

Technical summary

The `netlicensing_get_product` MCP tool in `netlicensing-mcp` interpolates a caller-controlled `product_number` argument directly into a REST URL path without any validation, allowing for path traversal. This vulnerability allows an authenticated MCP client to recover plaintext API key values that the token read tools intentionally mask, including admin-level APIKEY credentials. The vulnerability is a path traversal (CWE-22) that exploits the interaction between unsanitized string interpolation and `httpx`'s WHATWG URL normalization.

Defensive priority

Defenders should prioritize verifying the presence of this vulnerability in their inventory and upgrading to version 0.1.8 or later.

Recommended defensive actions

• Verify the presence of this vulnerability in your inventory
• Upgrade to version 0.1.8 or later
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is a path traversal (CWE-22) that exploits the interaction between unsanitized string interpolation and `httpx`'s WHATWG URL normalization. The `netlicensing_get_product` MCP tool in `netlicensing-mcp` interpolates a caller-controlled `product_number` 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 A

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.