diff --git a/src/rust/lqos_topology/src/lib.rs b/src/rust/lqos_topology/src/lib.rs
index b91f368e..a0baabd5 100644
--- a/src/rust/lqos_topology/src/lib.rs
+++ b/src/rust/lqos_topology/src/lib.rs
@@ -1796,11 +1796,23 @@ pub fn publish_topology_runtime_error_status(
 }
 
 fn parse_probe_ip(raw: &str) -> Option<IpAddr> {
-    raw.trim()
-        .split('/')
-        .next()
-        .filter(|value| !value.is_empty())
-        .and_then(|value| value.parse::<IpAddr>().ok())
+    let raw = raw.trim();
+    if raw.is_empty() {
+        return None;
+    }
+    let Some((addr, prefix)) = raw.split_once('/') else {
+        return raw.parse::<IpAddr>().ok();
+    };
+    if addr.is_empty() || prefix.is_empty() || prefix.contains('/') {
+        return None;
+    }
+    let ip = addr.parse::<IpAddr>().ok()?;
+    let prefix = prefix.parse::<u8>().ok()?;
+    match ip {
+        IpAddr::V4(_) if prefix <= 32 => Some(ip),
+        IpAddr::V6(_) if prefix <= 128 => Some(ip),
+        _ => None,
+    }
 }
 
 /// Returns the runtime stale cutoff in seconds for topology attachment health.
@@ -4597,7 +4609,7 @@ mod tests {
         apply_health_to_option, auto_attachment_option, build_effective_topology_artifacts,
         build_effective_topology_artifacts_from_canonical, build_shaping_inputs,
         collect_direct_circuit_node_ids, collect_direct_circuit_node_names,
-        compute_effective_state, publish_effective_topology_artifacts,
+        compute_effective_state, parse_probe_ip, publish_effective_topology_artifacts,
         publish_topology_runtime_error_status, ranked_auto_attachment_id,
         validate_effective_topology_network,
     };
@@ -4629,6 +4641,17 @@ mod tests {
         path
     }
 
+    #[test]
+    fn parse_probe_ip_rejects_invalid_cidr_suffixes() {
+        assert!(parse_probe_ip("192.0.2.1").is_some());
+        assert!(parse_probe_ip("192.0.2.1/32").is_some());
+        assert!(parse_probe_ip("2001:db8::1/128").is_some());
+        assert!(parse_probe_ip("192.0.2.1/not-a-prefix").is_none());
+        assert!(parse_probe_ip("192.0.2.1/33").is_none());
+        assert!(parse_probe_ip("2001:db8::1/129").is_none());
+        assert!(parse_probe_ip("192.0.2.1/24/extra").is_none());
+    }
+
     fn apply_effective_topology_to_network_json(
         config: &Config,
         canonical_network: &Value,
diff --git a/src/rust/lqos_topology/src/runtime/health.rs b/src/rust/lqos_topology/src/runtime/health.rs
index 47dc28a4..d8dc9432 100644
--- a/src/rust/lqos_topology/src/runtime/health.rs
+++ b/src/rust/lqos_topology/src/runtime/health.rs
@@ -7,9 +7,7 @@ use std::collections::HashMap;
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};
 
-use crate::{AttachmentProbeSpec, is_health_state_fresh};
-
-use super::probe::parse_probe_ip;
+use crate::{AttachmentProbeSpec, is_health_state_fresh, parse_probe_ip};
 
 pub(super) fn now_unix() -> Option<u64> {
     lqos_utils::unix_time::unix_now().ok()
diff --git a/src/rust/lqos_topology/src/runtime/probe.rs b/src/rust/lqos_topology/src/runtime/probe.rs
index 2d624376..13adbbbb 100644
--- a/src/rust/lqos_topology/src/runtime/probe.rs
+++ b/src/rust/lqos_topology/src/runtime/probe.rs
@@ -2,12 +2,11 @@ use anyhow::Result;
 use lqos_bus::{BusReply, BusRequest, BusResponse};
 use lqos_probe::{ProbeClass, ProbeObservation, ProbeRequest};
 use std::collections::HashMap;
-use std::net::IpAddr;
 use std::time::{Duration, Instant};
 use tokio::sync::mpsc::error::TrySendError;
 use tokio::sync::oneshot::error::TryRecvError;
 
-use crate::AttachmentProbeSpec;
+use crate::{AttachmentProbeSpec, parse_probe_ip};
 
 use super::TopologyBusSender;
 
@@ -94,14 +93,6 @@ fn bus_call(
     }
 }
 
-pub(super) fn parse_probe_ip(raw: &str) -> Option<IpAddr> {
-    raw.trim()
-        .split('/')
-        .next()
-        .filter(|value| !value.is_empty())
-        .and_then(|value| value.parse::<IpAddr>().ok())
-}
-
 pub(super) fn probe_specs(
     bus_tx: TopologyBusSender,
     specs: &[AttachmentProbeSpec],