diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cffbe27..47c4f7b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -54,3 +54,17 @@ jobs:
           # Optional: show only new issues if it's a pull request. The default value is `false`.
           only-new-issues: true
           working-directory: ./
+
+  fuzz:
+    name: fuzz tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ env.go-version }}
+          cache: true
+      - uses: actions/checkout@v4
+      - name: Build CLI binary
+        run: make build
+      - name: Run fuzz tests
+        run: make e2e-fuzz
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b7fe16d..55b87e5 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -47,6 +47,9 @@ jobs:
           MUMP2P_E2E_TOKEN_B64: ${{ secrets.MUMP2P_E2E_TOKEN_B64 }}
         run: make e2e-test
 
+      - name: Run Fuzz Tests
+        run: make e2e-fuzz
+
       - name: Upload Build Artifacts
         uses: actions/upload-artifact@v4
         with:
diff --git a/Makefile b/Makefile
index d02e8cb..e0adfe2 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ LD_FLAGS := -X github.com/getoptimum/mump2p-cli/internal/config.Domain=$(DOMAIN)
 
 .DEFAULT_GOAL := help
 
-.PHONY: all build run clean test help lint tag release print-cli-name e2e-test coverage
+.PHONY: all build run clean test help lint build tag release print-cli-name e2e-test e2e-fuzz coverage
 
 all: lint build
 
@@ -80,5 +80,22 @@ e2e-test: ## Run E2E tests against dist/ binary
 	fi
 	go test ./e2e -v -timeout 10m
 
+e2e-fuzz: ## Run fuzz tests against dist/ binary
+	@echo "Running fuzz tests..."
+	@if [ ! -f "$(BUILD_DIR)/$(CLI_NAME)-linux" ] && [ ! -f "$(BUILD_DIR)/$(CLI_NAME)-mac" ]; then \
+		echo "Error: No binary found in $(BUILD_DIR)/"; \
+		echo "Run 'make build' first with release credentials"; \
+		exit 1; \
+	fi
+	@echo "Fuzzing publish topic names..."
+	@go test ./e2e -run='^$$' -fuzz=FuzzPublishTopicName -fuzztime=1m -timeout=3m
+	@echo "Fuzzing publish messages..."
+	@go test ./e2e -run='^$$' -fuzz=FuzzPublishMessage -fuzztime=1m -timeout=3m
+	@echo "Fuzzing service URLs..."
+	@go test ./e2e -run='^$$' -fuzz=FuzzServiceURL -fuzztime=1m -timeout=3m
+	@echo "Fuzzing file paths..."
+	@go test ./e2e -run='^$$' -fuzz=FuzzFilePath -fuzztime=1m -timeout=3m
+	@echo "All fuzz tests passed!"
+
 help: ## Show help
-	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-20s\033[0m %s\n", $$1, $$2}'
\ No newline at end of file
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-20s\033[0m %s\n", $$1, $$2}'
diff --git a/cmd/health.go b/cmd/health.go
index 45e8c3b..4b07c3a 100644
--- a/cmd/health.go
+++ b/cmd/health.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"time"
 
 	"github.com/getoptimum/mump2p-cli/internal/config"
 	"github.com/getoptimum/mump2p-cli/internal/formatter"
@@ -42,7 +43,9 @@ var healthCmd = &cobra.Command{
 			return fmt.Errorf("failed to create request: %v", err)
 		}
 
-		resp, err := http.DefaultClient.Do(req)
+		// Use HTTP client with timeout to prevent hanging during fuzzing
+		client := &http.Client{Timeout: 10 * time.Second}
+		resp, err := client.Do(req)
 		if err != nil {
 			return fmt.Errorf("health check failed: %v", err)
 		}
diff --git a/cmd/tracer.go b/cmd/tracer.go
index 59ab38b..e830d2c 100644
--- a/cmd/tracer.go
+++ b/cmd/tracer.go
@@ -592,7 +592,9 @@ func resetStats(ctx context.Context, base, jwt string) error {
 	if jwt != "" {
 		req.Header.Set("Authorization", "Bearer "+jwt)
 	}
-	resp, err := http.DefaultClient.Do(req)
+	// Use HTTP client with timeout to prevent hanging during fuzzing
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
 	if err != nil {
 		return err
 	}
@@ -677,7 +679,9 @@ func proxyPublishRandom(base, jwt, clientID, topic string, length uint64) error
 	if !IsAuthDisabled() && jwt != "" {
 		req.Header.Set("Authorization", "Bearer "+jwt)
 	}
-	resp, err := http.DefaultClient.Do(req)
+	// Use HTTP client with timeout to prevent hanging during fuzzing
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
 	if err != nil {
 		return err
 	}
@@ -708,7 +712,9 @@ func proxySubscribe(base, jwt, topic, clientID string, threshold int) error {
 	if !IsAuthDisabled() && jwt != "" {
 		req.Header.Set("Authorization", "Bearer "+jwt)
 	}
-	resp, err := http.DefaultClient.Do(req)
+	// Use HTTP client with timeout to prevent hanging during fuzzing
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
 	if err != nil {
 		return err
 	}
diff --git a/e2e/cli_runner.go b/e2e/cli_runner.go
index a354699..0cd0156 100644
--- a/e2e/cli_runner.go
+++ b/e2e/cli_runner.go
@@ -2,22 +2,43 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"os"
 	"os/exec"
+	"time"
+)
+
+const (
+	// DefaultCommandTimeout is the timeout for CLI commands in fuzz tests
+	// This prevents hanging when fuzzing creates valid URLs that don't respond
+	DefaultCommandTimeout = 10 * time.Second
 )
 
 // RunCommand executes the CLI binary with given arguments and returns output
+// It uses a timeout to prevent hanging during fuzz tests
 func RunCommand(bin string, args ...string) (string, error) {
+	return RunCommandWithTimeout(bin, DefaultCommandTimeout, args...)
+}
+
+// RunCommandWithTimeout executes the CLI binary with a specific timeout
+func RunCommandWithTimeout(bin string, timeout time.Duration, args ...string) (string, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
 	var out bytes.Buffer
 	var stderr bytes.Buffer
 
-	cmd := exec.Command(bin, args...)
+	cmd := exec.CommandContext(ctx, bin, args...)
 	cmd.Env = os.Environ()
 	cmd.Stdout = &out
 	cmd.Stderr = &stderr
 
 	err := cmd.Run()
 	if err != nil {
+		// Check if timeout was exceeded
+		if ctx.Err() == context.DeadlineExceeded {
+			return stderr.String(), context.DeadlineExceeded
+		}
 		return stderr.String(), err
 	}
 	return out.String(), nil
diff --git a/e2e/fuzz_test.go b/e2e/fuzz_test.go
new file mode 100644
index 0000000..384c18f
--- /dev/null
+++ b/e2e/fuzz_test.go
@@ -0,0 +1,187 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// FuzzPublishTopicName tests the publish command with a topic name
+func FuzzPublishTopicName(f *testing.F) {
+	require.NotEmpty(f, cliBinaryPath, "CLI binary path must be set by TestMain")
+
+	f.Add("")
+	f.Add("\x00")
+	f.Add("../../../etc/passwd")
+	f.Add(strings.Repeat("a", 1000))
+	f.Add("test\n\r\t")
+	f.Add("test'; DROP TABLE")
+	f.Add("${HOME}")
+
+	f.Fuzz(func(t *testing.T, topic string) {
+		if len(topic) > 5000 {
+			t.Skip()
+		}
+
+		// For obviously invalid input, verify graceful error handling
+		if strings.Contains(topic, "\x00") {
+			args := []string{"publish", "--topic=" + topic, "--message=test"}
+			out, err := RunCommand(cliBinaryPath, args...)
+			require.Error(t, err, "CLI should reject null bytes in topic name")
+			// Verify error is handled gracefully (not a panic)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on topic with null byte: %v\nOutput: %s", err, out)
+			}
+			return
+		}
+
+		args := []string{"publish", "--topic=" + topic, "--message=test"}
+		out, err := RunCommand(cliBinaryPath, args...)
+		// For fuzzing, we need to detect failures - invalid topics should fail gracefully
+		// Valid topics might succeed (if subscribed) or fail (if not subscribed)
+		// The key is that the CLI should handle the input without panicking
+		if err != nil {
+			// Any error should be handled gracefully (not a panic or crash)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on topic %q: %v\nOutput: %s", topic, err, out)
+			}
+			// For invalid topics, errors are expected and acceptable
+			t.Logf("Command failed (expected for invalid input): %v\nOutput: %s", err, out)
+		}
+	})
+}
+
+// FuzzPublishMessage tests the publish command with a message.
+// This is distinct from FuzzPublishTopicName which tests topic name validation;
+// this test focuses on message content validation and handling.
+func FuzzPublishMessage(f *testing.F) {
+	require.NotEmpty(f, cliBinaryPath, "CLI binary path must be set by TestMain")
+
+	f.Add("")
+	f.Add("\x00")
+	f.Add(strings.Repeat("a", 10000))
+	f.Add("{\"test\": \"value\"}")
+	f.Add("test<script>alert(1)</script>")
+
+	f.Fuzz(func(t *testing.T, message string) {
+		if len(message) > 50000 {
+			t.Skip()
+		}
+
+		// For obviously invalid input, verify graceful error handling
+		if strings.Contains(message, "\x00") {
+			args := []string{"publish", "--topic=fuzz-test", "--message=" + message}
+			out, err := RunCommand(cliBinaryPath, args...)
+			require.Error(t, err, "CLI should reject null bytes in message")
+			// Verify error is handled gracefully (not a panic)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on message with null byte: %v\nOutput: %s", err, out)
+			}
+			return
+		}
+
+		args := []string{"publish", "--topic=fuzz-test", "--message=" + message}
+		out, err := RunCommand(cliBinaryPath, args...)
+		// For fuzzing, we need to detect failures - invalid messages should fail gracefully
+		// Valid messages might succeed (if topic is subscribed) or fail (if not subscribed)
+		// The key is that the CLI should handle the input without panicking
+		if err != nil {
+			// Any error should be handled gracefully (not a panic or crash)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on message %q: %v\nOutput: %s", message, err, out)
+			}
+			// For invalid messages, errors are expected and acceptable
+			t.Logf("Command failed (expected for invalid input): %v\nOutput: %s", err, out)
+		}
+	})
+}
+
+// FuzzServiceURL tests the health command with a service URL
+func FuzzServiceURL(f *testing.F) {
+	require.NotEmpty(f, cliBinaryPath, "CLI binary path must be set by TestMain")
+
+	f.Add("not-a-url")
+	f.Add("://broken")
+	f.Add("http://")
+	f.Add("http://localhost:-8080")
+	f.Add("http://localhost:99999")
+	f.Add("javascript:alert(1)")
+	f.Add("\x00")
+
+	f.Fuzz(func(t *testing.T, url string) {
+		if len(url) > 1000 {
+			t.Skip()
+		}
+
+		// For obviously invalid input, verify graceful error handling
+		if strings.Contains(url, "\x00") {
+			args := []string{"health", "--service-url=" + url}
+			out, err := RunCommand(cliBinaryPath, args...)
+			require.Error(t, err, "CLI should reject null bytes in service URL")
+			// Verify error is handled gracefully (not a panic)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on service URL with null byte: %v\nOutput: %s", err, out)
+			}
+			return
+		}
+
+		args := []string{"health", "--service-url=" + url}
+		out, err := RunCommand(cliBinaryPath, args...)
+		// For fuzzing, we need to detect failures - invalid URLs should fail gracefully
+		// Valid URLs might succeed (if proxy is reachable) or fail (if not)
+		// The key is that the CLI should handle the input without panicking
+		if err != nil {
+			// Any error should be handled gracefully (not a panic or crash)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on URL %q: %v\nOutput: %s", url, err, out)
+			}
+			// For invalid URLs, errors are expected and acceptable
+			t.Logf("Command failed (expected for invalid URL): %v\nOutput: %s", err, out)
+		}
+	})
+}
+
+// FuzzFilePath tests the publish command with a file path
+func FuzzFilePath(f *testing.F) {
+	require.NotEmpty(f, cliBinaryPath, "CLI binary path must be set by TestMain")
+
+	f.Add("")
+	f.Add("nonexistent.txt")
+	f.Add("../../../etc/passwd")
+	f.Add("/dev/null")
+	f.Add("test\x00file.txt")
+	f.Add(strings.Repeat("a", 500) + ".txt")
+
+	f.Fuzz(func(t *testing.T, filepath string) {
+		if len(filepath) > 2000 {
+			t.Skip()
+		}
+
+		// For obviously invalid input, verify graceful error handling
+		if strings.Contains(filepath, "\x00") {
+			args := []string{"publish", "--topic=fuzz-test", "--file=" + filepath}
+			out, err := RunCommand(cliBinaryPath, args...)
+			require.Error(t, err, "CLI should reject null bytes in file path")
+			// Verify error is handled gracefully (not a panic)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on file path with null byte: %v\nOutput: %s", err, out)
+			}
+			return
+		}
+
+		args := []string{"publish", "--topic=fuzz-test", "--file=" + filepath}
+		out, err := RunCommand(cliBinaryPath, args...)
+		// For fuzzing, we need to detect failures - invalid file paths should fail gracefully
+		// Valid file paths might succeed (if file exists and topic is subscribed) or fail (if not)
+		// The key is that the CLI should handle the input without panicking
+		if err != nil {
+			// Any error should be handled gracefully (not a panic or crash)
+			if strings.Contains(out, "panic") || strings.Contains(out, "fatal") {
+				t.Fatalf("CLI panicked or crashed on file path %q: %v\nOutput: %s", filepath, err, out)
+			}
+			// For invalid file paths, errors are expected and acceptable
+			t.Logf("Command failed (expected for invalid file path): %v\nOutput: %s", err, out)
+		}
+	})
+}
diff --git a/e2e/setup.go b/e2e/setup.go
index e90a14d..478ac3b 100644
--- a/e2e/setup.go
+++ b/e2e/setup.go
@@ -9,14 +9,16 @@ import (
 )
 
 // PrepareCLI sets up the test environment and returns the CLI binary path
+// Token setup is optional - if it fails, we continue without auth (useful for fuzz tests)
 func PrepareCLI() (cliPath string, cleanup func(), err error) {
-	tokenPath, err := SetupTokenFile()
-	if err != nil {
-		return "", nil, err
-	}
-	if err := os.Setenv("MUMP2P_AUTH_PATH", tokenPath); err != nil {
-		return "", nil, fmt.Errorf("failed to set MUMP2P_AUTH_PATH: %w", err)
+	tokenPath, tokenErr := SetupTokenFile()
+	if tokenErr == nil {
+		// Token setup succeeded, set it up
+		if err := os.Setenv("MUMP2P_AUTH_PATH", tokenPath); err != nil {
+			return "", nil, fmt.Errorf("failed to set MUMP2P_AUTH_PATH: %w", err)
+		}
 	}
+	// If token setup failed, we continue without auth (for fuzz tests that don't need it)
 	repoRoot, err := findRepoRoot()
 	if err != nil {
 		return "", nil, err
@@ -46,7 +48,9 @@ func PrepareCLI() (cliPath string, cleanup func(), err error) {
 	}
 
 	cleanup = func() {
-		_ = os.RemoveAll(filepath.Dir(tokenPath))
+		if tokenPath != "" {
+			_ = os.RemoveAll(filepath.Dir(tokenPath))
+		}
 	}
 
 	return cli, cleanup, nil