diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index c5b38cb..88b14f5 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -12,3 +12,8 @@
 **Vulnerability:** The code uses `readline()` in `R/aFIPC.R` to prompt the user. In non-interactive environments (e.g., CI/CD, automation scripts, agents), this can block execution or leave the process consuming resources.
 **Learning:** `readline()` should only be used when `interactive()` is true. Interactive prompts are insecure and unstable in automated contexts because they block execution unconditionally.
 **Prevention:** Always wrap `readline()` logic in an `if (interactive())` check or provide sensible defaults for non-interactive execution.
+
+## 2024-06-30 - Prevent Infinite Loop DoS in User Prompts
+**Vulnerability:** The code used `readline()` inside an unbounded `while` loop to validate user inputs. In environments where standard input is continuously piped or automated incorrectly, `readline()` repeatedly returns invalid inputs (like `""`), causing the loop to run infinitely. This leads to 100% CPU utilization and eventual service denial (DoS).
+**Learning:** Even when `interactive()` safeguards are present, user-provided loops over `readline()` are dangerous without an upper bound, as inputs can still be automated or maliciously piped in interactive-like environments.
+**Prevention:** Always include a `max_retries` counter (e.g., 5) and break or `stop()` when the limit is reached to prevent unbounded looping.
diff --git a/R/aFIPC.R b/R/aFIPC.R
index ecb5d05..a383c5d 100644
--- a/R/aFIPC.R
+++ b/R/aFIPC.R
@@ -89,8 +89,12 @@ autoFIPC <-
         )
       }
 
+      max_retries <- 5
+      retries <- 0
       n <- readline(prompt = "Is it correct? (1: Yes 2: No) : ")
       while (!grepl("^[0-9]+$", n)) {
+        retries <- retries + 1
+        if (retries >= max_retries) stop("Too many invalid inputs, preventing infinite loop.")
         n <- readline(prompt = "Is it correct? (1: Yes 2: No) : ")
       }
 
@@ -115,11 +119,15 @@ autoFIPC <-
       if (itemtype == '3PL' && length(oldformBILOGprior) == 0) {
         checkoldformBILOGprior <- function() {
           if (!interactive()) return(1L)
+          max_retries <- 5
+          retries <- 0
           n <-
             readline(
               prompt = "Do you want to use default BILOG-MG priors for oldform Data? (1: Yes 2: No) : "
             )
           while (!grepl("^[0-9]+$", n)) {
+            retries <- retries + 1
+            if (retries >= max_retries) stop("Too many invalid inputs, preventing infinite loop.")
             n <-
               readline(
                 prompt = "Do you want to use default BILOG-MG priors for oldform Data? (1: Yes 2: No) : "
@@ -330,11 +338,15 @@ autoFIPC <-
       if (itemtype == '3PL' && length(newformBILOGprior) == 0) {
         checknewformBILOGprior <- function() {
           if (!interactive()) return(1L)
+          max_retries <- 5
+          retries <- 0
           n <-
             readline(
               prompt = "Do you want to use default BILOG-MG priors for newform Data? (1: Yes 2: No) : "
             )
           while (!grepl("^[0-9]+$", n)) {
+            retries <- retries + 1
+            if (retries >= max_retries) stop("Too many invalid inputs, preventing infinite loop.")
             n <-
               readline(
                 prompt = "Do you want to use default BILOG-MG priors for newform Data? (1: Yes 2: No) : "
diff --git a/tests/testthat/test-security.R b/tests/testthat/test-security.R
index f7061aa..4cbbc6c 100644
--- a/tests/testthat/test-security.R
+++ b/tests/testthat/test-security.R
@@ -1,6 +1,6 @@
 test_that("autoFIPC handles non-interactive sessions securely to prevent DoS (checkCorrect)", {
   expect_error(
-    autoFIPC(
+    aFIPC::autoFIPC(
       newformXData = matrix(0, nrow=10, ncol=10),
       oldformYData = matrix(0, nrow=10, ncol=10),
       newformCommonItemNames = c("Item1"),