diff --git a/R/aFIPC.R b/R/aFIPC.R
index 6254651..918e19b 100644
--- a/R/aFIPC.R
+++ b/R/aFIPC.R
@@ -141,7 +141,7 @@ autoFIPC <-
       }
       for (attempt in seq_len(3)) {
         n <- readline(prompt = "Is it correct? (1: Yes 2: No) : ")
-        if (grepl("^[0-9]+$", n)) {
+        if (grepl("^[12]$", n)) {
           return(as.integer(n))
         }
       }
@@ -171,7 +171,7 @@ autoFIPC <-
               readline(
                 prompt = "Do you want to use default BILOG-MG priors for oldform Data? (1: Yes 2: No) : "
               )
-            if (grepl("^[0-9]+$", n)) {
+            if (grepl("^[12]$", n)) {
               return(as.integer(n))
             }
           }
@@ -390,7 +390,7 @@ autoFIPC <-
               readline(
                 prompt = "Do you want to use default BILOG-MG priors for newform Data? (1: Yes 2: No) : "
               )
-            if (grepl("^[0-9]+$", n)) {
+            if (grepl("^[12]$", n)) {
               return(as.integer(n))
             }
           }
diff --git a/tests/testthat/test-sentinel-validation.R b/tests/testthat/test-sentinel-validation.R
index 900f0ee..3d40ec0 100644
--- a/tests/testthat/test-sentinel-validation.R
+++ b/tests/testthat/test-sentinel-validation.R
@@ -35,3 +35,72 @@ test_that("autoFIPC validates boolean flags for newformBILOGprior, oldformBILOGp
     "Security Error: confirmCommonItems must be a single non-NA logical value or NULL"
   )
 })
+
+test_that("autoFIPC handles interactive confirmCommonItems readline DoS inputs correctly", {
+  # Mock interactive() and readline() to simulate abnormally large integer input that used to coerce to NA
+  mockery::stub(aFIPC::autoFIPC, 'interactive', TRUE)
+  mockery::stub(aFIPC::autoFIPC, 'readline', mockery::mock('9999999999999999999', '9999999999999999999', '9999999999999999999'))
+
+  expect_error(
+    aFIPC::autoFIPC(
+      newformXData = data.frame(item1 = c(1,0,1)),
+      oldformYData = data.frame(item1 = c(1,1,0)),
+      newformCommonItemNames = c('item1'),
+      oldformCommonItemNames = c('item1'),
+      confirmCommonItems = NULL
+    ),
+    "Too many invalid common item confirmation attempts"
+  )
+})
+
+test_that("autoFIPC handles interactive oldformBILOGprior readline DoS inputs correctly", {
+  mockery::stub(aFIPC::autoFIPC, 'interactive', TRUE)
+  mockery::stub(aFIPC::autoFIPC, 'readline', mockery::mock('1', '9999999999999999999', '9999999999999999999', '9999999999999999999'))
+
+  expect_error(
+    aFIPC::autoFIPC(
+      newformXData = data.frame(item1 = c(1,0,1)),
+      oldformYData = data.frame(item1 = c(1,1,0)),
+      newformCommonItemNames = c('item1'),
+      oldformCommonItemNames = c('item1'),
+      confirmCommonItems = NULL,
+      itemtype = '3PL',
+      oldformBILOGprior = NULL
+    ),
+    "Too many invalid oldform BILOG prior attempts"
+  )
+})
+
+test_that("autoFIPC handles interactive newformBILOGprior readline DoS inputs correctly", {
+  mockery::stub(aFIPC::autoFIPC, 'interactive', TRUE)
+  mockery::stub(aFIPC::autoFIPC, 'readline', mockery::mock('1', '1', '9999999999999999999', '9999999999999999999', '9999999999999999999'))
+
+  # Stub out mirt::mirt but instead of failing with an error, return a proper S4 object Mock
+  mockClass <- setClass("MockClass", slots=c(OptimInfo="list"))
+
+  mock_mirt <- function(data, model, itemtype, ...) {
+    if (identical(data, data.frame(item1 = c(1,1,0)))) {
+      return(mockClass(OptimInfo=list(secondordertest=TRUE)))
+    }
+    stop('Should not reach here')
+  }
+
+  mockery::stub(aFIPC::autoFIPC, 'mirt::mirt', mock_mirt)
+
+  mockery::stub(aFIPC::autoFIPC, 'mirt::extract.mirt', function(...) data.frame(a1=1, d=0, g=0, u=1))
+  mockery::stub(aFIPC::autoFIPC, 'mirt::coef', function(...) list(item1=c(a1=1, d=0, g=0, u=1)))
+
+  expect_error(
+    aFIPC::autoFIPC(
+      newformXData = data.frame(item1 = c(1,0,1)),
+      oldformYData = data.frame(item1 = c(1,1,0)),
+      newformCommonItemNames = c('item1'),
+      oldformCommonItemNames = c('item1'),
+      confirmCommonItems = NULL,
+      itemtype = '3PL',
+      oldformBILOGprior = NULL,
+      newformBILOGprior = NULL
+    ),
+    "Too many invalid newform BILOG prior attempts"
+  )
+})