diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index a8207a48..c142542a 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -2,3 +2,7 @@
 **Vulnerability:** Unvalidated inputs passed to `if()` statements can cause process crashes (`condition has length > 1`) or unexpected coercion vulnerabilities.
 **Learning:** In R, optional boolean parameters that default to `NULL` should be validated using explicit runtime type validation (e.g., `if (!is.null(flag) && (!is.logical(flag) || length(flag) != 1 || is.na(flag)))`).
 **Prevention:** Always implement explicit runtime type validation for optional boolean parameters.
+## 2024-07-28 - Fix integer coercion DoS vulnerability via interactive readline
+**Vulnerability:** Interactive `readline()` prompts parsing integers via `as.integer()` were loosely validated with `^[0-9]+$`. Large inputs coerced to `NA`, breaking `if` conditionals and causing crashes (Denial of Service).
+**Learning:** Weak regex for integers is dangerous since R's 32-bit limits can easily cause silent `NA` generation upon coercion.
+**Prevention:** Strictly bound validations for menu prompts (e.g., `^[12]$` instead of `^[0-9]+$`).
diff --git a/R/aFIPC.R b/R/aFIPC.R
index 62546519..918e19b1 100644
--- a/R/aFIPC.R
+++ b/R/aFIPC.R
@@ -141,7 +141,7 @@ autoFIPC <-
       }
       for (attempt in seq_len(3)) {
         n <- readline(prompt = "Is it correct? (1: Yes 2: No) : ")
-        if (grepl("^[0-9]+$", 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]$", n)) {
               return(as.integer(n))
             }
           }
diff --git a/tests/testthat/test-autoFIPC.R b/tests/testthat/test-autoFIPC.R
index 13cecd92..0a99b4cd 100644
--- a/tests/testthat/test-autoFIPC.R
+++ b/tests/testthat/test-autoFIPC.R
@@ -89,3 +89,13 @@ test_that("autoFIPC validates input types securely", {
     "Security Error: tryEM must be a single non-NA logical value"
   )
 })
+
+test_that("autoFIPC securely restricts input via regex for prompts", {
+  expect_true(grepl("^[12]$", "1"))
+  expect_true(grepl("^[12]$", "2"))
+  expect_false(grepl("^[12]$", "3"))
+  expect_false(grepl("^[12]$", "12"))
+  expect_false(grepl("^[12]$", "0"))
+  expect_false(grepl("^[12]$", "abc"))
+  expect_false(grepl("^[12]$", ""))
+})