diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index ebd965e6b..d15abc0b5 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -3047,7 +3047,8 @@ void LLRiggedVolume::update(const LLMeshSkinInfo* skin, LLVOAvatar* avatar, cons
 	LLMatrix4a mp[64];
 	LLMatrix4* mat = (LLMatrix4*) mp;
 	
-	for (U32 j = 0; j < skin->mJointNames.size(); ++j)
+	U32 maxJoints = llmin(skin->mJointNames.size(), 64);
+	for (U32 j = 0; j < maxJoints; ++j)
 	{
 		LLJoint* joint = avatar->getJoint(skin->mJointNames[j]);
 		if (joint)
@@ -3105,7 +3106,13 @@ void LLRiggedVolume::update(const LLMeshSkinInfo* skin, LLVOAvatar* avatar, cons
 					F32 w = wght[k];
 
 					LLMatrix4a src;
-					src.setMul(mp[idx[k]], w);
+					// Insure ref'd bone is in our clamped array of mats
+					llassert(idx[k] < 64);
+					// don't read garbage off the stack in release
+					if (idx[k] < 64)
+					{
+						src.setMul(mp[idx[k]], w);
+					}
 
 					final_mat.add(src);
 				}