{"id":"CVE-2026-55078","aliases":["GHSA-2mg2-p7r7-g27f"],"title":"Coder: Zip upload decompression lacks aggregate size limit, enabling denial of service","summary":"Coder: Zip upload decompression lacks aggregate size limit, enabling denial of service","severity":"medium","cvss":6.5,"cwe":["CWE-409","CWE-770"],"vendor":"coder","product":"github.com/coder/coder/v2","ecosystem":"go","affected":["github.com/coder/coder/v2 >= 2.34.0, < 2.34.2","github.com/coder/coder/v2 >= 2.33.0, < 2.33.8","github.com/coder/coder/v2 >= 2.30.0, < 2.32.7","github.com/coder/coder/v2 >= 2.17.0, < 2.29.17"],"patched":["github.com/coder/coder/v2 2.34.2","github.com/coder/coder/v2 2.33.8","github.com/coder/coder/v2 2.32.7","github.com/coder/coder/v2 2.29.17"],"published":"2026-07-06","updated":"2026-07-06","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-2mg2-p7r7-g27f","references":[{"url":"https://github.com/coder/coder/security/advisories/GHSA-2mg2-p7r7-g27f"},{"url":"https://github.com/coder/coder/pull/25877"},{"url":"https://github.com/advisories/GHSA-2mg2-p7r7-g27f"}],"tags":["ghsa","go"],"ingestedAt":"2026-07-06T21:45:52.961Z","epss":0.00602,"epssPercentile":0.47489,"slug":"CVE-2026-55078","body":"## Overview\n\n### Summary\n\n`POST /api/v2/files` converts zip uploads to tar in memory via `CreateTarFromZip`, which enforced a per-entry size limit but no aggregate limit on total decompressed output, writing to an unbounded in-memory buffer.\n\n> **Note:** Exploitation requires authenticated file-upload access and the impact is limited to availability (denial of service).\n\n### Impact\n\nAn authenticated user could upload a zip within the 100 MiB upload limit but containing many highly compressible entries whose decompressed size exhausted memory, crashing `coderd` before any RBAC check. Repeated requests could keep the service unavailable. This is a denial of service; it does not allow data disclosure or code execution.\n\n### Patches\n\nThe fix adds a metadata preflight check that sums projected entry sizes and a streaming writer that enforces the aggregate limit during decompression.\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 file-upload permissions to trusted users or place a reverse proxy with request-body size limits in front of `coderd`.\n\n### Resources\n\n- Fix: #25877\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22438) for independently disclosing this issue!\n\n## Affected packages\n\n- `github.com/coder/coder/v2 >= 2.34.0, < 2.34.2`\n- `github.com/coder/coder/v2 >= 2.33.0, < 2.33.8`\n- `github.com/coder/coder/v2 >= 2.30.0, < 2.32.7`\n- `github.com/coder/coder/v2 >= 2.17.0, < 2.29.17`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `github.com/coder/coder/v2 2.34.2`\n- `github.com/coder/coder/v2 2.33.8`\n- `github.com/coder/coder/v2 2.32.7`\n- `github.com/coder/coder/v2 2.29.17`","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}