security

AutoMapper 16.3.0 and 15.1.4 fix two high-severity advisories where deeply nested input bypassed MaxDepth and crashed the process with an uncatchable StackOverflowException. Here is which mapping paths were exposed and what changes when you upgrade.

Starting December 2, 2026, GitHub Actions blocks pull_request_target events in all public repositories unless an Actions event policy allows them. Brownouts hit on November 9 and 16. Here is how to find affected workflows and either migrate to pull_request or opt back in.

MXC is Microsoft's MIT-licensed SDK for running untrusted code, including model output, plugins and tools, under one deny-by-default policy that it maps to Seatbelt on macOS, bubblewrap on Linux and ProcessContainer on Windows. Here is what MXC SDK 1.0.1 and schema 1.0.0 actually define, how Copilot CLI hands it a policy per process, and what stays outside the box.

Microsoft Agent Framework for .NET 1.27.0 makes DefaultHttpRequestHandler throw HttpRequestException when its client-provider callback returns a client for a redirect destination. Here is why that hole existed, what breaks, and how to rewrite the callback.

Grpc.AspNetCore and Grpc.Net.Client 2.85.0 now apply MaxReceiveMessageSize to the decompressed size of gzip and deflate messages. A 260 KB request that inflates to 256 MiB is rejected with ResourceExhausted, but legitimate large compressed payloads can start failing too.

Turn on the local sandbox for everyday Copilot CLI work, move to a cloud sandbox when the code or the task should never touch your laptop, and use a dev container when the team needs the same reproducible toolchain. Compared on Copilot CLI 1.0.104: what each boundary isolates, what it leaks, what it costs, and how to stack them.

Anything you compile into a Flutter web build, including --dart-define values, ships to the browser in plain text. The only safe pattern is a small backend proxy that holds the key, authenticates the user, pins the model, and streams the Responses API SSE back. Full Dart shelf proxy and Flutter client, tested with Flutter 3.44, Dart 3.12, and http 1.6.

The October 25, 2026 out-of-band release (.NET 8.0.33, 9.0.22, 10.0.14, 11 RC3) fixes a Brotli buffer overflow, a Linux tarball ownership flaw, and two CVEs the October 13 patches did not fully close.

Turn on GitHub Copilot computer use in Copilot CLI and the Copilot app on macOS and Windows, grant the macOS Accessibility and Screen Recording permissions, approve apps per session or always, write prompts that keep the agent read-only, and lock it down with deny rules and the features.computerUse managed setting.

Enable GitHub Copilot local sandboxing in Copilot CLI 1.0.95 and the Copilot app, then lock down filesystem paths, outbound hosts, git/gh tokens and masked environment variables. Covers the settings.json keys, /sandbox policy, the bypass escape hatch, enterprise enforcement, and the gotchas on macOS, Linux and Windows.