diff --git a/nifticdf/CMakeLists.txt b/nifticdf/CMakeLists.txt
index b7d48480..8af8e395 100644
--- a/nifticdf/CMakeLists.txt
+++ b/nifticdf/CMakeLists.txt
@@ -33,6 +33,11 @@ endif()
 
 
 if(NIFTI_BUILD_TESTING AND NIFTI_BUILD_APPLICATIONS)
+  add_executable(${NIFTI_PACKAGE_PREFIX}nifticdf_range_test nifticdf_range_test.c)
+  target_link_libraries(${NIFTI_PACKAGE_PREFIX}nifticdf_range_test PRIVATE ${NIFTI_CDFLIB_NAME})
+  add_test( NAME ${NIFTI_PACKAGE_PREFIX}nifticdf_range_test
+            COMMAND $<TARGET_FILE:${NIFTI_PACKAGE_PREFIX}nifticdf_range_test> )
+
   foreach(DISTRIBUTION CORREL TTEST FTEST ZSCORE CHISQ BETA BINOM GAMMA POISSON NORMAL FTEST_NONC CHISQ_NONC LOGISTIC LAPLACE UNIFORM TTEST_NONC WEIBULL CHI INVGAUSS EXTVAL PVAL LOGPVAL LOG10PVAL )
     add_test( NAME ${NIFTI_PACKAGE_PREFIX}nifti_stats_${DISTRIBUTION}_test COMMAND $<TARGET_FILE:${NIFTI_PACKAGE_PREFIX}nifti_stats> 0:4:1 ${DISTRIBUTION})
     add_test( NAME q${NIFTI_PACKAGE_PREFIX}nifti_stats_${DISTRIBUTION}_test COMMAND $<TARGET_FILE:${NIFTI_PACKAGE_PREFIX}nifti_stats> -q 0:4:1 ${DISTRIBUTION})
diff --git a/nifticdf/nifticdf.c b/nifticdf/nifticdf.c
index bdab933f..d9dba0b9 100644
--- a/nifticdf/nifticdf.c
+++ b/nifticdf/nifticdf.c
@@ -1892,7 +1892,7 @@ static double T5,T6,T7,T8,T9,T10,T12,T13;
 /*
      Check arguments
 */
-    if(!(*which < 1 && *which > 4)) goto S30;
+    if(!(*which < 1 || *which > 4)) goto S30;
     if(!(*which < 1)) goto S10;
     *bound = 1.0e0;
     goto S20;
diff --git a/nifticdf/nifticdf_range_test.c b/nifticdf/nifticdf_range_test.c
new file mode 100644
index 00000000..63e607d6
--- /dev/null
+++ b/nifticdf/nifticdf_range_test.c
@@ -0,0 +1,50 @@
+/* cdfbin must reject an out-of-range "which" selector the way its ten
+   siblings in nifticdf.c do: *status = -1 and *bound = the limit. */
+
+#include <stdio.h>
+#include "nifticdf.h"
+
+static int check(int which, double expected_bound)
+{
+   int    status = 999;
+   double p = 0.5, q = 0.5, s = 2.0, xn = 5.0, pr = 0.5, ompr = 0.5;
+   double bound = -999.0;
+
+   cdfbin(&which, &p, &q, &s, &xn, &pr, &ompr, &status, &bound);
+
+   if( status != -1 || bound != expected_bound ) {
+      fprintf(stderr, "** cdfbin(which=%d): status=%d bound=%g,"
+                      " expected status=-1 bound=%g\n",
+              which, status, bound, expected_bound);
+      return 1;
+   }
+   printf("cdfbin(which=%d): status=%d bound=%g\n", which, status, bound);
+   return 0;
+}
+
+int main(void)
+{
+   int errs = 0;
+
+   errs += check(9, 4.0);   /* above the legal range */
+   errs += check(0, 1.0);   /* below the legal range */
+
+   /* a legal selector must still compute, not report a range error */
+   {
+      int    which = 1, status = 999;
+      double p = 0.0, q = 0.0, s = 2.0, xn = 5.0, pr = 0.5, ompr = 0.5;
+      double bound = -999.0;
+
+      cdfbin(&which, &p, &q, &s, &xn, &pr, &ompr, &status, &bound);
+      if( status != 0 ) {
+         fprintf(stderr, "** cdfbin(which=1): status=%d, expected 0\n", status);
+         errs++;
+      } else {
+         printf("cdfbin(which=1): status=0 p=%g\n", p);
+      }
+   }
+
+   if( errs ) { fprintf(stderr, "** %d failure(s)\n", errs); return 1; }
+   printf("nifticdf range test passed\n");
+   return 0;
+}