diff --git a/api/http/handler/endpoints/endpoint_agent_versions.go b/api/http/handler/endpoints/endpoint_agent_versions.go
index ced7d0b061..c132fdc189 100644
--- a/api/http/handler/endpoints/endpoint_agent_versions.go
+++ b/api/http/handler/endpoints/endpoint_agent_versions.go
@@ -4,6 +4,7 @@ import (
 	"net/http"
 
 	"github.com/portainer/portainer/api/http/security"
+	"github.com/portainer/portainer/api/internal/endpointutils"
 	"github.com/portainer/portainer/api/set"
 	httperror "github.com/portainer/portainer/pkg/libhttp/error"
 	"github.com/portainer/portainer/pkg/libhttp/response"
@@ -41,7 +42,7 @@ func (handler *Handler) agentVersions(w http.ResponseWriter, r *http.Request) *h
 
 	agentVersions := set.Set[string]{}
 	for _, endpoint := range filteredEndpoints {
-		if endpoint.Agent.Version != "" {
+		if endpointutils.IsAgentEndpoint(&endpoint) && endpoint.Agent.Version != "" {
 			agentVersions[endpoint.Agent.Version] = true
 		}
 	}
diff --git a/api/http/handler/endpoints/endpoint_agent_versions_test.go b/api/http/handler/endpoints/endpoint_agent_versions_test.go
new file mode 100644
index 0000000000..514460948b
--- /dev/null
+++ b/api/http/handler/endpoints/endpoint_agent_versions_test.go
@@ -0,0 +1,151 @@
+package endpoints
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	portainer "github.com/portainer/portainer/api"
+	"github.com/portainer/portainer/api/http/security"
+	"github.com/portainer/portainer/api/internal/testhelpers"
+
+	"github.com/segmentio/encoding/json"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func agentVersionsEndpoint(id portainer.EndpointID, endpointType portainer.EndpointType, version string) portainer.Endpoint {
+	return portainer.Endpoint{
+		ID:      id,
+		GroupID: 1,
+		Type:    endpointType,
+		Agent:   portainer.EnvironmentAgentData{Version: version},
+	}
+}
+
+func Test_AgentVersions(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		title     string
+		endpoints []portainer.Endpoint
+		expected  []string
+	}{
+		{
+			title:     "no environments returns an empty list",
+			endpoints: []portainer.Endpoint{},
+			expected:  []string{},
+		},
+		{
+			title: "excludes a local Docker environment carrying a stray agent version",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.DockerEnvironment, "2.1.0"),
+			},
+			expected: []string{},
+		},
+		{
+			title: "excludes a local Kubernetes environment carrying a stray agent version",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.KubernetesLocalEnvironment, "2.1.0"),
+			},
+			expected: []string{},
+		},
+		{
+			title: "excludes an Azure environment carrying a stray agent version",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.AzureEnvironment, "2.1.0"),
+			},
+			expected: []string{},
+		},
+		{
+			title: "includes a regular Docker agent environment",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.AgentOnDockerEnvironment, "2.39.0"),
+			},
+			expected: []string{"2.39.0"},
+		},
+		{
+			title: "includes an Edge Docker agent environment",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.EdgeAgentOnDockerEnvironment, "2.39.0"),
+			},
+			expected: []string{"2.39.0"},
+		},
+		{
+			title: "includes a regular Kubernetes agent environment",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.AgentOnKubernetesEnvironment, "2.39.0"),
+			},
+			expected: []string{"2.39.0"},
+		},
+		{
+			title: "includes an Edge Kubernetes agent environment",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.EdgeAgentOnKubernetesEnvironment, "2.39.0"),
+			},
+			expected: []string{"2.39.0"},
+		},
+		{
+			title: "excludes an agent environment that has not reported a version yet",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.AgentOnDockerEnvironment, ""),
+			},
+			expected: []string{},
+		},
+		{
+			title: "deduplicates identical versions reported by multiple agent environments",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.AgentOnDockerEnvironment, "2.39.0"),
+				agentVersionsEndpoint(2, portainer.AgentOnKubernetesEnvironment, "2.39.0"),
+			},
+			expected: []string{"2.39.0"},
+		},
+		{
+			title: "mixed fleet: only distinct agent versions surface, non-agent noise is excluded",
+			endpoints: []portainer.Endpoint{
+				agentVersionsEndpoint(1, portainer.AgentOnDockerEnvironment, "2.38.1"),
+				agentVersionsEndpoint(2, portainer.AgentOnDockerEnvironment, "2.39.0"),
+				agentVersionsEndpoint(3, portainer.EdgeAgentOnDockerEnvironment, "2.39.0"),
+				agentVersionsEndpoint(4, portainer.DockerEnvironment, "2.1.0"),
+				agentVersionsEndpoint(5, portainer.AgentOnDockerEnvironment, ""),
+			},
+			expected: []string{"2.38.1", "2.39.0"},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.title, func(t *testing.T) {
+			handler := setupEndpointListHandler(t, test.endpoints)
+
+			req := buildAgentVersionsRequest()
+
+			rr := httptest.NewRecorder()
+			handler.ServeHTTP(rr, req)
+
+			require.Equal(t, http.StatusOK, rr.Code)
+
+			body, err := io.ReadAll(rr.Body)
+			require.NoError(t, err)
+
+			var versions []string
+			require.NoError(t, json.Unmarshal(body, &versions))
+
+			assert.ElementsMatch(t, test.expected, versions)
+		})
+	}
+}
+
+func buildAgentVersionsRequest() *http.Request {
+	req := httptest.NewRequest(http.MethodGet, "/endpoints/agent_versions", nil)
+
+	ctx := security.StoreTokenData(req, &portainer.TokenData{ID: 1, Username: "admin", Role: 1})
+	req = req.WithContext(ctx)
+
+	restrictedCtx := security.StoreRestrictedRequestContext(req, &security.RestrictedRequestContext{UserID: 1, IsAdmin: true})
+	req = req.WithContext(restrictedCtx)
+
+	testhelpers.AddTestSecurityCookie(req, "Bearer dummytoken")
+
+	return req
+}