Hidden text on a web page could rewrite AWS Kiro's MCP config and run code on the developer's machine
At a Glance
- Serious damage. Customer data affected, security incident, or financial losses $10k–$100k.
Independent project · aggregated from public reports and may be unverified — see the primary source below · not affiliated with or endorsed by any company or product named.
What Happened
Intezer disclosed CVE-2026-10591 in AWS's agentic IDE Kiro. An attacker could hide instructions in a web page that Kiro fetches during a task, and the agent would rewrite its own Model Context Protocol configuration file without asking for user approval. Because MCP server entries specify commands to execute, the rewritten config gave the attacker arbitrary code execution on the developer's machine. AWS confirmed the fix shipped in Kiro 0.11.130, issued security bulletin 2026-037-aws, and recommended users update.
Case Analysis
Verified Facts
- CVE-2026-10591 let hidden web-page instructions rewrite Kiro's MCP configuration without user approval
- A rewritten MCP config yields arbitrary code execution because entries specify commands to run
- AWS patched it in Kiro 0.11.130 and published security bulletin 2026-037-aws
Not Publicly Confirmed
- Whether the flaw was exploited in the wild
Operational Lessons
- An agent's own configuration files must be outside the set of files it can write during a task
- Any file that defines executable commands deserves an explicit, unskippable human approval gate
Primary Source
Remote Code Execution in AWS Kiro, CVE-2026-10591 (Intezer)research.intezer.com ↗Case Record
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