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MCP security

3 journal entries tagged MCP security.

An aluminium selector holds removable cartridges beside a separate slot returning a strip of paper

Article24 September 20265 min read

Prompt injection in MCP: first win the tool call, then redirect the agent

A benchmark study separates two trust boundaries: the metadata that wins a tool call and the return content that redirects the agent after it runs.

A two-stage MCP prompt injection study wins tool calls with optimised metadata, then redirects agents through malicious tool returns. Both boundaries need policy.

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A support-ticket card beside a computing module with an exposed service-connection cable

Article19 September 20265 min read

Prompt injection in AWS AgentCore: when a vaulted credential becomes readable

Unit 42’s controlled support-agent demonstration traces a poisoned ticket through shell access to a replayable downstream credential.

Unit 42’s AWS AgentCore prompt injection research shows how shell access exposed an in-use credential, with lessons for tool scope and runtime isolation.

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A mechanical agent arm crosses a cobalt workspace boundary towards a sensitive local-file card

Article1 September 20265 min read

SiYuan fixes prompt-injection path to SSH keys and cloud credentials

CVE-2026-82233 shows how an AI agent’s ordinary upload tool can turn hidden instructions and an approved tool call into sensitive local-file exposure.

CVE-2026-82233 let SiYuan’s AI agent copy sensitive local files through MCP, showing why tool approvals need action-level policy.

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