diff --git a/libs/linglong/tests/ll-tests/src/linglong/utils/io_test.cpp b/libs/linglong/tests/ll-tests/src/linglong/utils/io_test.cpp
index 3e3216e4e..e1ae59c14 100644
--- a/libs/linglong/tests/ll-tests/src/linglong/utils/io_test.cpp
+++ b/libs/linglong/tests/ll-tests/src/linglong/utils/io_test.cpp
@@ -15,6 +15,8 @@
 #include "linglong/utils/unique_fd.h"
 
 #include <array>
+#include <climits>
+#include <cstddef>
 #include <cstring>
 #include <string>
 
@@ -259,6 +261,14 @@ TEST(RingBuffer, ClearResetsState)
     EXPECT_EQ(buf->size(), 0);
 }
 
+TEST(RingBuffer, CreateRejectsOversizedCapacity)
+{
+    // A power-of-two capacity beyond vector::max_size() must be reported via
+    // the empty optional instead of escaping the noexcept boundary.
+    auto oversized = std::size_t{ 1 } << (sizeof(std::size_t) * CHAR_BIT - 1);
+    EXPECT_FALSE(RingBuffer::create(oversized).has_value());
+}
+
 TEST(EventLoop, CreateAndWaitTimeout)
 {
     auto loop = EventLoop::create();
diff --git a/libs/utils/src/linglong/utils/io/ring_buffer.h b/libs/utils/src/linglong/utils/io/ring_buffer.h
index 95c265aae..2d2113086 100644
--- a/libs/utils/src/linglong/utils/io/ring_buffer.h
+++ b/libs/utils/src/linglong/utils/io/ring_buffer.h
@@ -31,8 +31,16 @@ class alignas(hardware_constructive_interference_size) RingBuffer
             return std::nullopt;
         }
 
-        std::vector<std::byte> data(cap);
-        return RingBuffer{ std::move(data), cap - 1 };
+        if (cap > std::vector<std::byte>().max_size()) {
+            return std::nullopt;
+        }
+
+        try {
+            std::vector<std::byte> data(cap);
+            return RingBuffer{ std::move(data), cap - 1 };
+        } catch (...) {
+            return std::nullopt;
+        }
     }
 
     RingBuffer(const RingBuffer &) = delete;