[ctx]ctxseccontext security: attacks on the harness and context layer of AI agents, plus exploited-now news, hunting and playbooks.

← Context & Harness Attacks · markdown

official (AWS Security Bulletin 2026-176-AWS and GHSA-4wq9-grf3-qg2p, Nov 10, 2026)

AWS API MCP Server's deny and confirmation rules could be skipped for operations with consecutive capital letters; update to 1.5.1

  • Who is affected: locally run servers with a custom security policy that lists affected operations. AWS says the remote AWS API MCP Server offering and the READ_OPERATIONS_ONLY and REQUIRE_MUTATION_CONSENT settings are not affected.
  • Do: upgrade awslabs.aws-api-mcp-server to 1.5.1 or later; there is no workaround. Patch forks too.
  • Check: CloudTrail for operations on your denyList made by the IAM identity your MCP server uses.
  • Lesson: an MCP server's own allow/deny list is a convenience, not a boundary; scope the IAM role so denied actions fail at AWS as well.

Sources: AWS Security Bulletin 2026-176-AWS: CVE-2026-125271, AWS API MCP Server security policy bypass · GitHub advisory GHSA-4wq9-grf3-qg2p (awslabs/mcp)