diff --git a/CHANGELOG.md b/CHANGELOG.md
index d82f11269..63fb1e484 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
-## [5.0.56] - 2024-03-??
+## [5.0.56] - 2024-02-24
 
 * set the ZeroMQ port to 0 by default, hence assuming a single-server mode (the port can be specified in the _*config.ini*_ file)
+* corrected the P-V Diagram line length calculation inside a FORTRAN subroutine, added capacity checks to prevent potential out-of-bounds accesses
 
 ## [5.0.55] - 2024-02-22
 
diff --git a/Julia/pv_line.jl b/Julia/pv_line.jl
deleted file mode 100644
index e2bc359fa..000000000
--- a/Julia/pv_line.jl
+++ /dev/null
@@ -1,17 +0,0 @@
-x1 = 100
-y1 = 98
-x2 = 98
-y2 = 95
-
-dx = abs(x2 - x1) + 1
-dy = abs(y2 - y1) + 1
-dp = sqrt(dx^2 + dy^2)
-dt = 1.0 / dp / 100.0
-
-println("dx: $dx, dy: $dy, dp: $dp, dt: $dt")
-
-for t in 0:dt:1
-    x = x1 + t * (x2 - x1)
-    y = y1 + t * (y2 - y1)
-    #println("($x, $y)")
-end
\ No newline at end of file
diff --git a/src/fits.f90 b/src/fits.f90
index 7e0ef401e..6fe097fa5 100644
--- a/src/fits.f90
+++ b/src/fits.f90
@@ -8679,7 +8679,7 @@ recursive subroutine ws_pv_request(user) BIND(C, name='ws_pv_request')
       type(c_ptr) :: pid
       integer(kind=c_int) :: rc
 
-      integer :: frame, first, last, length, npoints, i, j, max_threads
+      integer :: frame, first, last, length, capacity, npoints, i, j, max_threads
       real :: dx, dy, dp, t, dt
       integer(c_int) :: x1, x2, y1, y2
       integer :: prev_x, prev_y, cur_x, cur_y
@@ -8762,8 +8762,8 @@ recursive subroutine ws_pv_request(user) BIND(C, name='ws_pv_request')
       print *, 'dx:', dx, 'dy:', dy, 'dp:', dp, 'dt:', dt
 
       ! over-allocate the points array
-      npoints = ceiling(2*dp)
-      allocate (points(2,npoints))
+      capacity = ceiling(2*dp)
+      allocate (points(2,capacity))
 
       ! first enumerate points along the line
       npoints = 0
@@ -8781,9 +8781,12 @@ recursive subroutine ws_pv_request(user) BIND(C, name='ws_pv_request')
          end if
 
          t = t + dt
+
+         ! break the loop if capacity is exceeded
+         if (npoints .ge. capacity) exit
       end do
 
-      print *, 'npoints:', npoints
+      print *, 'npoints:', npoints, 'capacity:', capacity
 
       ! there will be at least one point
       ! allocate the pv array using an appropriate astronomical orientation convention
@@ -8980,7 +8983,7 @@ subroutine get_pv_diagram(item, req, pixels, width, height, pmin, pmax, pmean, p
       type(c_ptr) :: pid
       integer(kind=c_int) :: rc
 
-      integer :: frame, first, last, length, i, j, max_threads
+      integer :: frame, first, last, length, i, j, max_threads, capacity
       real :: dx, dy, dp, t, dt
       integer(c_int) :: x1, x2, y1, y2
       integer :: prev_x, prev_y, cur_x, cur_y
@@ -9039,8 +9042,8 @@ subroutine get_pv_diagram(item, req, pixels, width, height, pmin, pmax, pmean, p
       print *, 'dx:', dx, 'dy:', dy, 'dp:', dp, 'dt:', dt
 
       ! over-allocate the points array
-      npoints = ceiling(2*dp)
-      allocate (points(2,npoints))
+      capacity = ceiling(2*dp)
+      allocate (points(2,capacity))
 
       ! first enumerate points along the line
       npoints = 0
@@ -9058,9 +9061,12 @@ subroutine get_pv_diagram(item, req, pixels, width, height, pmin, pmax, pmean, p
          end if
 
          t = t + dt
+
+         ! break the loop if capacity is exceeded
+         if (npoints .ge. capacity) exit
       end do
 
-      print *, 'npoints:', npoints
+      print *, 'npoints:', npoints, 'capacity:', capacity
 
       ! there will be at least one point
       ! allocate the pv array using an appropriate astronomical orientation convention
diff --git a/src/version.h b/src/version.h
index 3182fc623..201245d37 100644
--- a/src/version.h
+++ b/src/version.h
@@ -2,7 +2,7 @@
 
 #define VERSION_MAJOR 5
 #define VERSION_MINOR 0
-#define VERSION_SUB 55
+#define VERSION_SUB 56
 
 #define STR_HELPER(x) #x
 #define STR(x) STR_HELPER(x)