{"id":"GHSA-f962-qm93-mj4c","summary":"Coder's unbounded memory allocation in provisioner file upload allows authenticated denial of service","details":"### Summary\n\n`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\n\n### Impact\n\nAn 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.\n\n### Patches\n\nThe fix validates `FileSize` against an upper bound (`MaxFileSize = 100 MiB`) before allocation.\n\nThe fix was backported to all supported release lines:\n\n| Release line | Patched version |\n|---|---|\n| 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) |\n| 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) |\n| 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) |\n| 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) |\n\n### Workarounds\n\nRestrict access to the provisioner daemon serve endpoint to trusted provisioner daemon service accounts.\n\n### Resources\n\n- Fix: #25710\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22442) for independently disclosing this issue!","aliases":["CVE-2026-55079","GO-2026-5911"],"modified":"2026-07-07T16:11:41.116744380Z","published":"2026-07-06T20:54:41Z","database_specific":{"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-07-06T20:54:41Z","nvd_published_at":null,"cwe_ids":["CWE-789"]},"references":[{"type":"WEB","url":"https://github.com/coder/coder/security/advisories/GHSA-f962-qm93-mj4c"},{"type":"WEB","url":"https://github.com/coder/coder/pull/25710"},{"type":"PACKAGE","url":"https://github.com/coder/coder"}],"affected":[{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.34.0"},{"fixed":"2.34.2"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-f962-qm93-mj4c/GHSA-f962-qm93-mj4c.json"}},{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.33.0"},{"fixed":"2.33.8"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-f962-qm93-mj4c/GHSA-f962-qm93-mj4c.json"}},{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.30.0"},{"fixed":"2.32.7"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-f962-qm93-mj4c/GHSA-f962-qm93-mj4c.json"}},{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.24.0"},{"fixed":"2.29.17"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-f962-qm93-mj4c/GHSA-f962-qm93-mj4c.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H"}]}