Affected: Google LLC AWS S3 Crypto SDK for GoLang

A vulnerability in the in-band key negotiation exists in the AWS S3 Crypto SDK for GoLang versions prior to V2. An attacker with write access to the targeted bucket can change the encryption algorithm of an object in the bucket, which can then allow them to change AES-GCM to AES-CTR. Using this in combination with a decryption oracle can reveal the authentication key used by AES-GCM as decrypting the GMAC tag leaves the authentication key recoverable as an algebraic equation. It is recommended to update your SDK to V2 or later, and re-encrypt your files.

Affected: Go: github.com/go-viper/mapstructure/v2

### Summary

Use of this library in a security-critical context may result in leaking sensitive information, if used to process sensitive fields.

### Details

OpenBao (and presumably HashiCorp Vault) have surfaced error messages from `mapstructure` as follows:

https://github.com/openbao/openbao/blob/98c3a59c040efca724353ca46ca79bd5cdbab920/sdk/framework/field_data.go#L43-L50

```go _, _, err := d.getPrimitive(field, schema) if err != nil { return fmt.Errorf("error converting input for field %q: %w", field, err) } ```

where this calls `mapstructure.WeakDecode(...)`: https://github.com/openbao/openbao/blob/98c3a59c040efca724353ca46ca79bd5cdbab920/sdk/framework/field_data.go#L181-L193

```go

func (d *FieldData) getPrimitive(k string, schema *FieldSchema) (interface{}, bool, error) { raw, ok := d.Raw[k] if !ok { return nil, false, nil }

switch t := schema.Type; t { case TypeBool: var result bool if err := mapstructure.WeakDecode(raw, &result); err != nil { return nil, false, err } return result, true, nil ```

Notably, `WeakDecode(...)` eventually calls one of the decode helpers, which surfaces the original value via `strconv` helpers:

https://github.com/go-viper/mapstructure/blob/8c61ec1924fcfa522f9fc6b4618c672db61d1a38/mapstructure.go#L720-L727

https://github.com/go-viper/mapstructure/blob/8c61ec1924fcfa522f9fc6b4618c672db61d1a38/mapstructure.go#L791-L798

https://github.com/go-viper/mapstructure/blob/8c61ec1924fcfa522f9fc6b4618c672db61d1a…