{"id":"CVE-2026-97731","title":"MinIO through 7aac2a2 does not verify that every x-amz-* header present on a request also appears in the client-supplied X-Amz-SignedHeaders list","summary":"MinIO through 7aac2a2 does not verify that every x-amz-* header present on a request also appears in the client-supplied X-Amz-SignedHeaders list. extractSignedHeaders() in cmd/signature-v4-utils.go iterates only the claimed list and nev…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","cwe":["CWE-347"],"vendor":"MinIO","product":"MinIO","affected":["MinIO <= 7aac2a2c5b7c882e68c1ce017d8256be2feea27f"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T03:16:59.697","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97731","references":[{"url":"https://github.com/pgsty/silo/commit/1233254309b15571f101b2b26d531951ceaeef1e","label":"cve@mitre.org"},{"url":"https://silo.pgsty.com/about/security-advisories/#sn-2026-011","label":"cve@mitre.org"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T03:58:52.649Z","slug":"CVE-2026-97731","body":"## Overview\n\nMinIO through 7aac2a2 does not verify that every x-amz-* header present on a request also appears in the client-supplied X-Amz-SignedHeaders list. extractSignedHeaders() in cmd/signature-v4-utils.go iterates only the claimed list and never enumerates the headers that actually arrived, and thus a header that arrives unsigned is neither hashed into the canonical request nor rejected. Because cmd/api-router.go dispatches CopyObject on the presence of x-amz-copy-source alone, the holder of a presigned PUT URL scoped to a single object can add that header to the unmodified URL and cause a server-side copy, executed as the signer, of any object the signing key can read. A grant to write one object becomes a read of every bucket that key can reach. Amazon S3 rejects the equivalent request with HTTP 403 AccessDenied. The minio/minio GitHub repository was archived in April 2026; pgsty/silo before 1233254 is also affected.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}