AWS STS error: number of regions does not match number of endpoints

After upgrading to Vault 1.19.x you may encounter the error:

{"errors":["number of regions does not match number of endpoints"]}

For example this may be with an AWS Secrets engine that was confirmed to be working prior to the upgrade with an older version of Vault prior to 1.19.x.

To resolve the issue explicitly set the default endpoint and region by configuring STS within Vault like:

{
...
  "sts_region" = "us-east-1"
  "sts_endpoint" = "https://sts.amazonaws.com"
...
}

Alternatively if AWS Environment variables are applicable in the deployment, ensure that the related parameters are set (AWS_REGION, etc).

Useful Links

• Vault Docs - Important Changes: AWS STS configuration can fail with unspecified STS endpoints
• GitHub Issue - 1.19.0 Breaking Bug: AWS STS 400 Error: {"errors":["number of regions does not match number of endpoints"]} #29869