blaze is a prototype and has not had a security review. This page says where the parts that matter for security are described and how to report a problem.

Please report a vulnerability privately through GitHub's "Report a vulnerability" button on the repository's Security tab rather than in a public issue. There is no bounty and no promised response time.

A miscompile, where a program built with blaze behaves differently from the one the pinned nightly's rustc builds, is a correctness bug and can be reported in a normal issue.

Only the latest release, and main, get fixes.

• The daemon runs your build. It runs as your user and loads workspaces. It writes no build file into the checkout: a workspace builds into its directory under blaze's root ($BLAZE_HOME, else ~/.cache/blaze). See docs/cargo.md, "Where a build writes".
• Build scripts and proc macros run in a sandbox. Every build script is compiled by blaze and run in the sandbox tests run in; proc macros are compiled to WebAssembly and run in Wasmtime, in the daemon. Where no sandbox can be made, blaze stops with an error and does not run them outside one, unless you opt out by a documented setting. The sandbox bounds what user code of a build can read and write; it has not been reviewed as a security boundary against hostile code. Tests and the programs blaze run starts are your code run as you: plain blaze test runs them outside any sandbox, as cargo does. See docs/cargo.md, "Build scripts and proc macros run in a sandbox" and "Proc macros run as WebAssembly".
• The daemon's socket is for one user. It lives in a directory that must be owned by you with mode 0700, the socket is 0600, and a connection from another user is refused before its request is read. blaze serve --http ADDR listens on TCP only with a bearer token in BLAZE_API_TOKEN. On Windows the directory and peer checks are not implemented. See docs/cargo.md, "Files".
• The local store is trusted. Its records carry checksums against damage, not against tampering: anyone who can write to blaze's root can put code into your builds. Keep it writable by you alone.
• There is no shared store. The blaze of today pulls from and pushes to no remote cache, and holds no cloud credentials. The plan for one, with its trust and signing, is docs/remote-cache.md; nothing of it is a setting yet.
• What blaze fetches is checked. Registry packages are checked against the checksums of the lock file, and the toolchain and the pinned LLVM against the sha256 blaze pins.
• blaze refuses what its checks find, and they are not all of rustc's. Its borrow checker refuses the errors it finds, which is not yet every error rustc gives, so a program rustc rejects may build. See docs/borrowck.md.