A new defect has been detected and assigned to matt.kangas@10gen.com in Coverity Connect http://coverity.mongodb.com//sourcebrowser.htm?projectId=10001#mergedDefectId=15733
The defect was flagged by checker SIZECHECK in
file /src/mongo/db/exec/2d.cpp
function mongo::TwoD::work(long *)
and this ticket was created by matt.kangas@10gen.com

It's complaining about line 68 in 2d.cpp
https://github.com/mongodb/mongo/blame/master/src/mongo/db/exec/2d.cpp#L66-L70

 _am = static_cast<TwoDAccessMethod*>( collection->getIndexCatalog()->getIndex( _descriptor ) );

CID 15733 (#3-2 of 3): Allocation too small for type (SIZECHECK)10. size_error: Allocating 72 bytes to pointer of type mongo::TwoDAccessMethod, which needs at least 112 bytes.