feat: [#428] upgrade default Prometheus image to v3.5.1

- update domain config and renderer expectations

- align docs/examples in source comments

- mark Prometheus remediation subtask complete

Author: josecelano

docs/issues/428-docker-vulnerability-analysis-apr8-2026.md

@@ -103,7 +103,7 @@ For each image, execute these steps in order:
 #### 6. Prometheus (`prom/prometheus:v3.5.0`)
 
 - [x] Analysis and triage completed
-- [ ] Easy remediation implemented (if available)
+- [x] Easy remediation implemented (if available)
 - [ ] Image rebuilt and validated
 - [ ] Trivy re-scan completed and compared
 - [ ] Scan docs updated

src/application/command_handlers/show/info/docker_images.rs

@@ -12,7 +12,7 @@ pub struct DockerImagesInfo {
     /// `MySQL` Docker image reference (e.g. `mysql:8.4`), present when `MySQL` is configured
     pub mysql: Option<String>,
 
-    /// Prometheus Docker image reference (e.g. `prom/prometheus:v3.5.0`), present when configured
+    /// Prometheus Docker image reference (e.g. `prom/prometheus:v3.5.1`), present when configured
     pub prometheus: Option<String>,
 
     /// Grafana Docker image reference (e.g. `grafana/grafana:12.3.1`), present when configured

src/domain/prometheus/config.rs

@@ -21,7 +21,7 @@ const DEFAULT_SCRAPE_INTERVAL_SECS: u32 = 15;
 pub const PROMETHEUS_DOCKER_IMAGE_REPOSITORY: &str = "prom/prometheus";
 
 /// Docker image tag for the Prometheus container
-pub const PROMETHEUS_DOCKER_IMAGE_TAG: &str = "v3.5.0";
+pub const PROMETHEUS_DOCKER_IMAGE_TAG: &str = "v3.5.1";
 
 /// Prometheus metrics collection configuration
 ///
@@ -95,7 +95,7 @@ impl PrometheusConfig {
     /// use torrust_tracker_deployer_lib::domain::prometheus::PrometheusConfig;
     ///
     /// let image = PrometheusConfig::docker_image();
-    /// assert_eq!(image.full_reference(), "prom/prometheus:v3.5.0");
+    /// assert_eq!(image.full_reference(), "prom/prometheus:v3.5.1");
     /// ```
     #[must_use]
     pub fn docker_image() -> DockerImage {

src/infrastructure/templating/docker_compose/template/renderer/docker_compose.rs

@@ -407,7 +407,7 @@ mod tests {
             "Rendered output should contain prometheus service"
         );
         assert!(
-            rendered_content.contains("image: prom/prometheus:v3.5.0"),
+            rendered_content.contains("image: prom/prometheus:v3.5.1"),
             "Should use Prometheus v3.5.0 image"
         );
         assert!(
@@ -466,7 +466,7 @@ mod tests {
 
         // Verify Prometheus service is NOT present
         assert!(
-            !rendered_content.contains("image: prom/prometheus:v3.5.0"),
+            !rendered_content.contains("image: prom/prometheus:v3.5.1"),
             "Should not contain Prometheus service when config absent"
         );
         assert!(

src/infrastructure/templating/docker_compose/template/wrappers/docker_compose/context/prometheus.rs

@@ -18,7 +18,7 @@ use super::service_topology::ServiceTopology;
 /// Uses `ServiceTopology` to share the common topology structure with other services.
 #[derive(Serialize, Debug, Clone)]
 pub struct PrometheusServiceContext {
-    /// Docker image reference (e.g. `prom/prometheus:v3.5.0`)
+    /// Docker image reference (e.g. `prom/prometheus:v3.5.1`)
     pub image: String,
 
     /// Service topology (ports and networks)

src/shared/docker_image.rs

@@ -130,7 +130,7 @@ mod tests {
     fn it_should_create_from_str_tuple() {
         let image = DockerImage::from(("prom/prometheus", "v3.5.0"));
 
-        assert_eq!(image.full_reference(), "prom/prometheus:v3.5.0");
+        assert_eq!(image.full_reference(), "prom/prometheus:v3.5.1");
     }
 
     #[test]