GHSA-f962-qm93-mj4c Coder's unbounded memory allocation in provisioner file upload allows authenticated denial of service

• Go github.com/coder/coder/v2: >= 2.34.0, < 2.34.2 → fixed in 2.34.2 • Go github.com/coder/coder/v2: >= 2.33.0, < 2.33.8 → fixed in 2.33.8 • Go github.com/coder/coder/v2: >= 2.30.0, < 2.32.7 → fixed in 2.32.7 • Go github.com/coder/coder/v2: >= 2.24.0, < 2.29.17 → fixed in 2.29.17

Summary `NewDataBuilder` in `provisionersdk/proto/dataupload.go` allocated a byte slice using the client-supplied `FileSize` from a `DataUpload` message without an upper-bound check. Although the DRPC wire limit is 4 MiB, the `FileSize` value itself was unconstrained Impact An authenticated user able to reach the provisioner daemon serve endpoint could send a roughly 50-byte message declaring a huge `FileSize` (for example 1 TiB), triggering an unrecoverable Go out-of-memory abort that terminates `coderd`. This is a single-message denial of service affecting the entire deployment. Patches The fix validates `FileSize` against an upper bound (`MaxFileSize = 100 MiB`) before allocation. The fix was backported to all supported release lines: | Release line | Patched version | |---|---| | 2.34 | v2.34.2 | | 2.33 | v2.33.8 | | 2.32 | v2.32.7 | | 2.29 (ESR) | v2.29.17 | Workarounds Restrict access to the provisioner daemon serve endpoint to trusted provisioner daemon service accounts. Resources • Fix: #25710 Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22442) for independently disclosing this issue!