{"id":"CVE-2026-27607","summary":"RustFS's Missing Post Policy Validation leads to Arbitrary Object Write","details":"RustFS is a distributed object storage system built in Rust. In versions 1.0.0-alpha.56 through 1.0.0-alpha.82, RustFS does not validate policy conditions in presigned POST uploads (PostObject), allowing attackers to bypass content-length-range, starts-with, and Content-Type constraints. This enables unauthorized file uploads exceeding size limits, uploads to arbitrary object keys, and content-type spoofing, potentially leading to storage exhaustion, unauthorized data access, and security bypasses. Version 1.0.0-alpha.83 fixes the issue.","aliases":["GHSA-w5fh-f8xh-5x3p"],"modified":"2026-04-10T05:37:15.524051Z","published":"2026-02-25T02:10:28.086Z","database_specific":{"cwe_ids":["CWE-20","CWE-863"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27607.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27607.json"},{"type":"ADVISORY","url":"https://github.com/rustfs/rustfs/security/advisories/GHSA-w5fh-f8xh-5x3p"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27607"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/rustfs/rustfs","events":[{"introduced":"3f717292bf69a6cf5fffa0e41253fd1ce08ec5cb"},{"fixed":"9824171995b58da071c18b5243299bc69e6ec4a7"}]}],"versions":["1.0.0-alpha.56","1.0.0-alpha.57","1.0.0-alpha.58","1.0.0-alpha.59","1.0.0-alpha.60","1.0.0-alpha.61","1.0.0-alpha.62","1.0.0-alpha.63","1.0.0-alpha.64","1.0.0-alpha.65","1.0.0-alpha.66","1.0.0-alpha.67","1.0.0-alpha.68","1.0.0-alpha.69","1.0.0-alpha.70","1.0.0-alpha.71","1.0.0-alpha.72","1.0.0-alpha.73","1.0.0-alpha.74","1.0.0-alpha.75","1.0.0-alpha.76","1.0.0-alpha.77","1.0.0-alpha.78","1.0.0-alpha.79","1.0.0-alpha.80","1.0.0-alpha.81","1.0.0-alpha.82"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27607.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H"}]}