argoproj/argo-workflows · error

expected bearer token to be a JWT and therefore have 3 dot-d

Error message

expected bearer token to be a JWT and therefore have 3 dot-delimited parts

What it means

ClaimSetWithBearerToken split the bearer token on '.' and did not get 3 parts, so the token is not a JWT and its claims cannot be extracted. This guards the server-auth mode where the server's own SA token is decoded into an identity.

Source

Thrown at server/auth/serviceaccount/claims.go:47

		return ClaimSetWithX509(restConfig)
	}
	return nil, nil
}

func ClaimSetWithBearerToken(restConfig *rest.Config) (*types.Claims, error) {
	bearerToken := restConfig.BearerToken
	if bearerToken == "" {
		// should only ever be used for service accounts
		data, err := os.ReadFile(restConfig.BearerTokenFile)
		if err != nil {
			return nil, fmt.Errorf("failed to read bearer token file: %w", err)
		}
		bearerToken = string(data)
	}

	parts := strings.SplitN(bearerToken, ".", 3)
	if len(parts) != 3 {
		return nil, fmt.Errorf("expected bearer token to be a JWT and therefore have 3 dot-delimited parts")
	}
	payload := parts[1]
	data, err := base64.RawStdEncoding.DecodeString(payload)
	if err != nil {
		return nil, fmt.Errorf("failed to decode bearer token's JWT payload: %w", err)
	}

	claims := &types.Claims{}
	err = json.Unmarshal(data, &claims)
	if err != nil {
		return nil, fmt.Errorf("failed to unmarshal bearer token's JWT payload: %w", err)
	}

	// attempt to derive SA name and namespace from Subject
	// "system:serviceaccount:argo:jenkins" -> "argo", "jenkins"
	// note that the SA name can have a colon in it, although the rest cannot
	parts = strings.SplitN(claims.Subject, ":", 4)
	if len(parts) < 4 {

View on GitHub (pinned to 35bff19146)

Solutions

1. Ensure the configured bearer token is a JWT (standard Kubernetes SA tokens are)
2. Use a token file containing the full three-segment JWT

When it happens

Trigger: Thrown at server/auth/serviceaccount/claims.go:47 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of argoproj/argo-workflows@35bff19146 (2026-09-03). Data as JSON: /api/errors/451d3745f20004b3. Report an issue: GitHub.