diff --git a/src/BRepOffset/BRepOffset_Tool.cxx b/src/BRepOffset/BRepOffset_Tool.cxx
index 38f21f0988..af3ac106e1 100644
--- a/src/BRepOffset/BRepOffset_Tool.cxx
+++ b/src/BRepOffset/BRepOffset_Tool.cxx
@@ -1345,7 +1345,11 @@ static TopoDS_Edge AssembleEdge(const BOPDS_PDS& pDS,
     {
       TopoDS_Vertex CV, V11, V12, V21, V22;
       TopExp::CommonVertex( CurEdge, anEdge, CV );
-      Standard_Boolean IsAutonomCV = IsAutonomVertex( CV, pDS, F1, F2 );
+      Standard_Boolean IsAutonomCV = Standard_False;
+      if (!CV.IsNull())
+      {
+        IsAutonomCV = IsAutonomVertex(CV, pDS, F1, F2);
+      }
       if (IsAutonomCV)
       {
         aGlueTol = BRep_Tool::Tolerance(CV);
diff --git a/src/Extrema/Extrema_ExtCS.cxx b/src/Extrema/Extrema_ExtCS.cxx
index c50a6b28c3..68cc4138d2 100644
--- a/src/Extrema/Extrema_ExtCS.cxx
+++ b/src/Extrema/Extrema_ExtCS.cxx
@@ -105,7 +105,7 @@ void Extrema_ExtCS::Perform(const Adaptor3d_Curve& C,
   mySqDist.Clear();
   Standard_Integer i, j;
   Standard_Integer NbT, NbU, NbV;
-  NbT = NbU = NbV = 10;
+  NbT = 12; NbU = NbV = 10;
   GeomAbs_CurveType myCtype  = C.GetType();
 
   myDone = Standard_False;
diff --git a/src/IntTools/IntTools_BeanFaceIntersector.cxx b/src/IntTools/IntTools_BeanFaceIntersector.cxx
index cbae85db3e..5796905a3c 100644
--- a/src/IntTools/IntTools_BeanFaceIntersector.cxx
+++ b/src/IntTools/IntTools_BeanFaceIntersector.cxx
@@ -913,7 +913,17 @@ void IntTools_BeanFaceIntersector::ComputeUsingExtremum()
     }
 
     GeomAdaptor_Curve aGACurve(aCurve, anarg1, anarg2);
-    Extrema_ExtCS theExtCS(aGACurve, aGASurface, Tol, Tol);
+    Extrema_ExtCS theExtCS;
+    theExtCS.Initialize(aGASurface, myUMinParameter, myUMaxParameter,
+                                    myVMinParameter, myVMaxParameter,  Tol, Tol);
+    Standard_Real first = aCurve->FirstParameter(), last = aCurve->LastParameter();
+    if (aCurve->IsPeriodic() || 
+       (anarg1 >= first - Precision::PConfusion() && anarg2 <= last + Precision::PConfusion()))
+    {
+      //Extrema_ExtCS theExtCS(aGACurve, aGASurface, Tol, Tol);
+      theExtCS.Perform(aGACurve, anarg1, anarg2);
+    }
+
     myExtrema = theExtCS; 
     
     if(myExtrema.IsDone() && (myExtrema.NbExt() || myExtrema.IsParallel())) {
diff --git a/src/ProjLib/ProjLib_CompProjectedCurve.cxx b/src/ProjLib/ProjLib_CompProjectedCurve.cxx
index 919db15608..6d5e6698aa 100644
--- a/src/ProjLib/ProjLib_CompProjectedCurve.cxx
+++ b/src/ProjLib/ProjLib_CompProjectedCurve.cxx
@@ -636,8 +636,8 @@ void ProjLib_CompProjectedCurve::Init()
   Standard_Boolean FromLastU = Standard_False,
                    isSplitsComputed = Standard_False;
 
-  const Standard_Real aTol3D = Precision::Confusion();
-  Extrema_ExtCS CExt(myCurve->Curve(), mySurface->Surface(), aTol3D, aTol3D);
+  const Standard_Real aTolExt = Precision::PConfusion();
+  Extrema_ExtCS CExt(myCurve->Curve(), mySurface->Surface(), aTolExt, aTolExt);
   if (CExt.IsDone() && CExt.NbExt())
   {
     // Search for the minimum solution.
diff --git a/tests/bugs/modalg_5/bug25232_8 b/tests/bugs/modalg_5/bug25232_8
index 61892b8be4..49d0e7f63a 100644
--- a/tests/bugs/modalg_5/bug25232_8
+++ b/tests/bugs/modalg_5/bug25232_8
@@ -27,5 +27,5 @@ mkvolume result fcon3 fp
 checkprops result -s 1706.51 
 checkshape result
 
-checknbshapes result -vertex 5 -edge 6 -wire 2 -face 2 -shell 1 -solid 1 -compsolid 0 -compound 0 -shape 17
+checknbshapes result -vertex 4 -edge 5 -wire 2 -face 2 -shell 1 -solid 1 -compsolid 0 -compound 0 -shape 15
 checkview -display result -2d -path ${imagedir}/${test_image}.png
diff --git a/tests/bugs/modalg_7/bug27087 b/tests/bugs/modalg_7/bug27087
new file mode 100644
index 0000000000..c244d28763
--- /dev/null
+++ b/tests/bugs/modalg_7/bug27087
@@ -0,0 +1,16 @@
+puts "========"
+puts "OCC27087"
+puts "========"
+puts ""
+#######################################################
+# [Regression to OCCT 6.7.1] BRepExtrema_DistShapeShape gives wrong result
+#######################################################
+
+smallview
+restore [locate_data_file bug27087.brep] a
+explode a
+distmini r a_1 a_2
+if { [dval r_val] > 0.0001 } { puts "Error: too big deviation, should be 0!" }
+
+fit
+checkview -screenshot -2d -path ${imagedir}/${test_image}.png