diff --git a/lib/tdeck_ui/Telemetry/LocationMessagePolicy.cpp b/lib/tdeck_ui/Telemetry/LocationMessagePolicy.cpp
index 595aa181..919ab4ab 100644
--- a/lib/tdeck_ui/Telemetry/LocationMessagePolicy.cpp
+++ b/lib/tdeck_ui/Telemetry/LocationMessagePolicy.cpp
@@ -56,6 +56,16 @@ LocationMessageDecision classifyInboundLocationMessage(
         return decision;
     }
 
+    if (!isValidPeerLocationInput(decision.location,
+                                  decision.meta,
+                                  message.received_at_millis)) {
+        decision.kind = LocationMessageKind::MALFORMED_LOCATION;
+        decision.log_malformed = true;
+        setChatActions(decision, human_text);
+        decision.drop = !human_text;
+        return decision;
+    }
+
     decision.kind = decision.meta.has_cease && decision.meta.cease
                         ? LocationMessageKind::VALID_CEASE
                         : LocationMessageKind::VALID_LOCATION;
diff --git a/lib/tdeck_ui/Telemetry/LocationShareState.cpp b/lib/tdeck_ui/Telemetry/LocationShareState.cpp
index 24fa8dd0..21a10905 100644
--- a/lib/tdeck_ui/Telemetry/LocationShareState.cpp
+++ b/lib/tdeck_ui/Telemetry/LocationShareState.cpp
@@ -36,6 +36,26 @@ bool locationInRange(const LocationTelemetry& location) {
 
 }  // namespace
 
+bool isValidPeerLocationInput(
+    const LocationTelemetry& location,
+    const CustomLocationMeta& meta,
+    uint64_t received_at_millis) {
+    if ((meta.has_expires && meta.expires_millis < 0) ||
+        (meta.has_approx_radius && meta.approx_radius_meters < 0)) {
+        return false;
+    }
+    uint64_t source_timestamp_millis = 0;
+    if (!effectiveTimestampMillis(location, meta, source_timestamp_millis)) {
+        return false;
+    }
+    if (meta.has_cease && meta.cease) return true;
+    if (meta.has_expires &&
+        received_at_millis >= static_cast<uint64_t>(meta.expires_millis)) {
+        return true;
+    }
+    return locationInRange(location);
+}
+
 bool PeerLocationStore::peerEquals(const PeerId& left, const PeerId& right) {
     return std::memcmp(left.bytes, right.bytes, PEER_ID_SIZE) == 0;
 }
@@ -103,8 +123,7 @@ PeerLocationResult PeerLocationStore::apply(
     const LocationTelemetry& location,
     const CustomLocationMeta& meta,
     uint64_t received_at_millis) {
-    if ((meta.has_expires && meta.expires_millis < 0) ||
-        (meta.has_approx_radius && meta.approx_radius_meters < 0)) {
+    if (!isValidPeerLocationInput(location, meta, received_at_millis)) {
         return PeerLocationResult::INVALID_ARGUMENT;
     }
 
diff --git a/lib/tdeck_ui/Telemetry/LocationShareState.h b/lib/tdeck_ui/Telemetry/LocationShareState.h
index a0be8999..4b9cfbf5 100644
--- a/lib/tdeck_ui/Telemetry/LocationShareState.h
+++ b/lib/tdeck_ui/Telemetry/LocationShareState.h
@@ -36,6 +36,13 @@ enum class PeerLocationResult : uint8_t {
     INVALID_ARGUMENT,
 };
 
+// Mirrors the argument-domain checks performed by PeerLocationStore::apply().
+// Staleness and capacity remain store-state decisions, not wire validity.
+bool isValidPeerLocationInput(
+    const LocationTelemetry& location,
+    const CustomLocationMeta& meta,
+    uint64_t received_at_millis);
+
 class PeerLocationStore {
 public:
     PeerLocationStore() = default;
diff --git a/tests/native/test_location_message_policy.cpp b/tests/native/test_location_message_policy.cpp
index 6274b148..7f93c1a3 100644
--- a/tests/native/test_location_message_policy.cpp
+++ b/tests/native/test_location_message_policy.cpp
@@ -3,6 +3,7 @@
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
+#include <limits>
 
 #include "Telemetry/LocationMessagePolicy.h"
 
@@ -184,6 +185,13 @@ void malformedLocationFailsClosedButTextSurvives() {
     decision = Telemetry::classifyInboundLocationMessage(message);
     CHECK(decision.kind == Telemetry::LocationMessageKind::MALFORMED_LOCATION);
     CHECK(!decision.apply_location);
+
+    Fields unusable_timestamp =
+        validFields(std::numeric_limits<uint64_t>::max());
+    message = input(peer(3), unusable_timestamp);
+    decision = Telemetry::classifyInboundLocationMessage(message);
+    CHECK(decision.kind == Telemetry::LocationMessageKind::MALFORMED_LOCATION);
+    CHECK(!decision.apply_location && decision.drop && decision.log_malformed);
 }
 
 void ceaseAndAuthenticatedSenderIsolation() {