MCP server published to PyPI with confusable package name
Summary
Attacker publishes a Python package with a name confusingly similar to a popular MCP server (hyphen vs. underscore, missing dash). Install completes; MCP server behaves like the real one for basic tool calls but exfiltrates arguments.
Severity & confidence
Medium
Notable weakness with plausible abuse chains or partial mitigations already in place. Track, and resolve as part of your normal hardening cadence.
Confirmed
Observed directly by Jiffy scanners or validated by multiple independent sources. Indicators are reliable enough to drive automated action.
Indicators
Observed patterns and artifacts associated with this entry. Each indicator can be copied into your detection stack or SIEM.
(?i)mcp[-_](?:serever|serer|sever|servr)
Detection rule
A YARA-style pseudo-rule auto-generated from the indicators above. Useful as a starting point — adapt the syntax for your target detection platform.
rule jiffy_ti_2026_000048
{
meta:
source = "jiffy-intel"
severity = "medium"
description = "Auto-generated from Jiffy Intel indicators"
strings:
$content_pattern_0 = "(?i)mcp[-_](?:serever|serer|sever|servr)"
condition:
$content_pattern_0
}Auto-generated from the indicators above. Adapt syntax for your detection stack before deploying.
Affected tools
| Tool | Versions | Status |
|---|---|---|
| Any MCP-capable agent | * | vulnerable |
Example artifacts
Sanitized examples of artifacts Jiffy has observed exhibiting this pattern. Publisher handles are redacted; version ranges and status reflect the most recent scan.
- mcp_serever_toolsMCP serverRemoved
- mcp-severe-helpersMCP serverRemoved
How to remediate
- 01Allowlist exact PyPI/npm package names for MCP servers.
- 02Reject installs of near-typosquats.
Timeline & sources
Timeline
- First observedFeb 21, 20261 month ago
- Last updatedApr 20, 2026today
- PublishedMar 9, 20261 month ago
Sources
References
MITRE ATT&CK T1195 — Supply Chain Compromise
https://attack.mitre.org/techniques/T1195/OWASP LLM-03: Supply Chain (2026)
https://genai.owasp.org/llmrisk/llm-03-2026/Jiffy Research — The AI Artifact Supply Chain
https://blog.jiffylabs.ai/posts/the-ai-artifact-supply-chainScan for patterns like this
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