diff --git a/src/avalanche/peermanager.cpp b/src/avalanche/peermanager.cpp
--- a/src/avalanche/peermanager.cpp
+++ b/src/avalanche/peermanager.cpp
@@ -76,21 +76,24 @@
             return i;
         }
 
-        // We undershooted.
+        // We undershot.
         if (slots[i].precedes(slot)) {
             begin = i + 1;
+            if (begin >= slots.size()) {
+                break;
+            }
             bottom = slots[begin].start;
             continue;
         }
 
-        // We overshooted.
+        // We overshot.
         if (slots[i].follows(slot)) {
             end = i;
             top = slots[end].start;
             continue;
         }
 
-        // We have an unalocated slot.
+        // We have an unallocated slot.
         return NO_PEER;
     }