--- a/dom/canvas/WebGLContextBuffers.cpp
+++ b/dom/canvas/WebGLContextBuffers.cpp
@@ -506,18 +506,20 @@ WebGLContext::DeleteBuffer(WebGLBuffer* 
     if (IsWebGL2()) {
         fnClearIfBuffer(mBoundCopyReadBuffer);
         fnClearIfBuffer(mBoundCopyWriteBuffer);
         fnClearIfBuffer(mBoundPixelPackBuffer);
         fnClearIfBuffer(mBoundPixelUnpackBuffer);
         fnClearIfBuffer(mBoundUniformBuffer);
         fnClearIfBuffer(mBoundTransformFeedback->mGenericBufferBinding);
 
-        for (auto& binding : mBoundTransformFeedback->mIndexedBindings) {
-            fnClearIfBuffer(binding.mBufferBinding);
+        if (!mBoundTransformFeedback->mIsActive) {
+            for (auto& binding : mBoundTransformFeedback->mIndexedBindings) {
+                fnClearIfBuffer(binding.mBufferBinding);
+            }
         }
 
         for (auto& binding : mIndexedUniformBufferBindings) {
             fnClearIfBuffer(binding.mBufferBinding);
         }
     }
 
     for (int32_t i = 0; i < mGLMaxVertexAttribs; i++) {