diff --git a/apps/runloop-engine/internal/db/postgres.go b/apps/runloop-engine/internal/db/postgres.go
index 44da94c..7890bce 100644
--- a/apps/runloop-engine/internal/db/postgres.go
+++ b/apps/runloop-engine/internal/db/postgres.go
@@ -3,11 +3,12 @@ package db
 import (
 	"context"
 	"fmt"
+	"math"
 	"time"
 
 	"github.com/jackc/pgx/v5/pgxpool"
-	"github.com/runloop/runloop-engine/internal/config"
 	"github.com/rs/zerolog/log"
+	"github.com/runloop/runloop-engine/internal/config"
 )
 
 // Postgres represents a PostgreSQL database connection
@@ -15,6 +16,20 @@ type Postgres struct {
 	Pool *pgxpool.Pool
 }
 
+// clampInt32 narrows an int from config (env-var-derived) to the int32 range
+// pgxpool requires. Values ≤ 0 produce 0 so callers can fall back to library
+// defaults; large values are pinned to math.MaxInt32 instead of silently
+// wrapping into a negative number.
+func clampInt32(v int) int32 {
+	if v <= 0 {
+		return 0
+	}
+	if v >= math.MaxInt32 {
+		return math.MaxInt32
+	}
+	return int32(v)
+}
+
 // NewPostgres creates a new PostgreSQL connection pool
 func NewPostgres(cfg *config.Config) (*Postgres, error) {
 	ctx := context.Background()
@@ -25,9 +40,12 @@ func NewPostgres(cfg *config.Config) (*Postgres, error) {
 		return nil, fmt.Errorf("unable to parse database URL: %w", err)
 	}
 
-	// Set pool configuration
-	poolConfig.MaxConns = int32(cfg.DatabaseMaxConns)
-	poolConfig.MinConns = int32(cfg.DatabaseMaxIdle)
+	// Set pool configuration. pgxpool stores pool sizes as int32, so clamp
+	// the int values from config to the int32 range. In practice these come
+	// from env vars and are small (≤ a few hundred); the clamp is a safety
+	// belt that also satisfies CodeQL's incorrect-integer-conversion rule.
+	poolConfig.MaxConns = clampInt32(cfg.DatabaseMaxConns)
+	poolConfig.MinConns = clampInt32(cfg.DatabaseMaxIdle)
 
 	// Create connection pool
 	pool, err := pgxpool.NewWithConfig(ctx, poolConfig)
diff --git a/apps/runloop-engine/internal/db/postgres_test.go b/apps/runloop-engine/internal/db/postgres_test.go
new file mode 100644
index 0000000..11335fe
--- /dev/null
+++ b/apps/runloop-engine/internal/db/postgres_test.go
@@ -0,0 +1,29 @@
+package db
+
+import (
+	"math"
+	"testing"
+)
+
+// clampInt32 keeps pgxpool's int32 fields safe from out-of-range int values
+// coming out of the env-var config.
+
+func TestClampInt32(t *testing.T) {
+	cases := []struct {
+		in   int
+		want int32
+	}{
+		{0, 0},
+		{-1, 0},
+		{math.MinInt32, 0},
+		{1, 1},
+		{200, 200},
+		{math.MaxInt32, math.MaxInt32},
+		{math.MaxInt32 + 1, math.MaxInt32},
+	}
+	for _, c := range cases {
+		if got := clampInt32(c.in); got != c.want {
+			t.Errorf("clampInt32(%d) = %d, want %d", c.in, got, c.want)
+		}
+	}
+}
diff --git a/apps/runloop-engine/internal/queue/backend_kafka.go b/apps/runloop-engine/internal/queue/backend_kafka.go
index 42caa9e..fbb2683 100644
--- a/apps/runloop-engine/internal/queue/backend_kafka.go
+++ b/apps/runloop-engine/internal/queue/backend_kafka.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"math"
 	"strconv"
 	"sync"
 	"time"
@@ -43,8 +44,8 @@ type KafkaBackend struct {
 	workerID string
 
 	mu       sync.Mutex
-	readers  map[string]*kafka.Reader // key = topic+groupId — consumer
-	writers  map[string]*kafka.Writer // key = brokers-joined
+	readers  map[string]*kafka.Reader  // key = topic+groupId — consumer
+	writers  map[string]*kafka.Writer  // key = brokers-joined
 	ackState map[string]*kafka.Message // handle -> message (for commit lookup)
 }
 
@@ -303,13 +304,24 @@ func (k *KafkaBackend) Nack(ctx context.Context, q *QueueDef, handle string, req
 		}
 	}
 
-	// Increment attempts header and re-publish.
+	// Increment attempts header and re-publish. The header's previous count
+	// is read from an attacker-controllable bytestream, so do the +1 in int64
+	// (no overflow) and clamp into int32 right at the cast — a maliciously
+	// huge value shouldn't wrap into a negative attempt count and bypass the
+	// max-attempts check below.
 	attempts := int32(0)
 	out := make([]kafka.Header, 0, len(msg.Headers))
 	for _, h := range msg.Headers {
 		if h.Key == "x-attempts" {
 			n, _ := strconv.Atoi(string(h.Value))
-			attempts = int32(n) + 1
+			v := int64(n) + 1
+			if v < 1 {
+				v = 1
+			}
+			if v > math.MaxInt32 {
+				v = math.MaxInt32
+			}
+			attempts = int32(v)
 			continue
 		}
 		if h.Key == "x-last-error" {