AWS Security Digest·Week 32 of 2026·Aug 3-9, 2026·3 items
AgentCore Gets Long-Lived Runtimes, and a Temporal Policy Language
Bedrock AgentCore Runtime Instances reach general availability, letting agents run on dedicated EC2 instances for up to 14 days instead of the 8-hour microVM limit. AWS open-sources Dogwood, a Cedar-compatible policy language with temporal logic for governing sequences of agent tool calls. A path traversal bug in the AWS Transform MCP Server gets patched.
In this issue2medium1info
Highlights
2 items
$ tail -f /var/log/aws-security.log
medium/Feature Launch/
Bedrock AgentCore Runtime Instances Reach General Availability
AgentCore Runtime Instances let agents run on dedicated EC2 instances - including GPU-accelerated, memory-optimized, and compute-optimized families - for sessions of up to 14 days, versus the 8-hour cap on the existing serverless microVM option.
AWS handles provisioning, patching, scaling, and lifecycle management. Available in nine regions: N. Virginia, Ohio, Oregon, Mumbai, Singapore, Sydney, Tokyo, Frankfurt, and Ireland.
Bedrock AgentCore
info/Feature Launch/
AWS Open-Sources Dogwood, a Temporal Policy Language for AI Agents
Dogwood (Apache 2.0) extends AWS's Cedar authorization language with Metric First-Order Temporal Logic, so policies can reason over sequences of an agent's tool calls rather than one request at a time - enforcing prerequisites ("approve before acting"), rate limits across time windows, ordered tool usage, and running totals.
Every valid Cedar policy remains valid Dogwood syntax; Cedar's point-in-time model stays available for simple access-control decisions.
Cedar
CVEs & Vulnerabilities
1 item
$ cat /var/reports/CVE_REPORT.txt
medium/CVE/
CVE-2026-18953: Path Traversal in AWS Transform MCP Server
The get_resource tool in awslabs.aws-transform-mcp-server failed to validate the savePath parameter, allowing files to be written outside the intended directory and potentially enabling local code execution. Affects 0.1.0-0.1.4; fixed in 0.1.5. Reported by Drew Raines.
Affected
awslabs.aws-transform-mcp-server 0.1.0-0.1.4
Fixed In
awslabs.aws-transform-mcp-server 0.1.5
MCP
Key Takeaway
1 item
$ cat WEEKLY_SUMMARY.md
Dogwood is worth a close read if you are operating agents with any autonomy: point-in-time authorization, which is what Cedar and most IAM policies do, cannot stop an agent from doing the right thing ten times in a row when the eleventh time is the problem. Pair it with the new 14-day AgentCore runtimes, which make that kind of extended, stateful agent operation the norm rather than the exception.
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