diff --git a/third_party/angle/src/libANGLE/renderer/vulkan/FramebufferVk.cpp b/third_party/angle/src/libANGLE/renderer/vulkan/FramebufferVk.cpp
index 0deef0df8a..1a3a422799 100644
--- a/third_party/angle/src/libANGLE/renderer/vulkan/FramebufferVk.cpp
+++ b/third_party/angle/src/libANGLE/renderer/vulkan/FramebufferVk.cpp
@@ -2237,6 +2237,19 @@ gl::FramebufferStatus FramebufferVk::checkStatus(const gl::Context *context) con
             gl::err::kFramebufferIncompleteUnsupportedSeparateDepthStencilBuffers);
     }
 
+    // Vulkan requires VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT when multiple
+    // attachments alias the same memory, and forbids two written aliases in one
+    // subpass. ANGLE never sets MAY_ALIAS_BIT, so reject duplicate colour
+    // attachments here (mirrors FramebufferD3D::checkStatus). The frontend only
+    // checks this when WebGL compatibility is enabled.
+    ASSERT(!context->isWebGL() || mState.colorAttachmentsAreUniqueImages());
+    if (!context->isWebGL() && !mState.colorAttachmentsAreUniqueImages())
+    {
+        return gl::FramebufferStatus::Incomplete(
+            GL_FRAMEBUFFER_UNSUPPORTED,
+            gl::err::kFramebufferIncompleteUnsupportedNonUniqueAttachments);
+    }
+
     return gl::FramebufferStatus::Complete();
 }