diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index bc5c6e1..dbb94d5 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -12,3 +12,8 @@
 **Vulnerability:** Raw `stop()` and `warning()` calls without `call. = FALSE` in `llcont.R` and `vuongtest.R` exposed execution stack/call details when raised.
 **Learning:** While some instances of `stop()` inside `tryCatch()` were previously fixed to hide the call stack, other standalone exceptions and warnings still leaked call context. Security must be consistently applied across the entire codebase.
 **Prevention:** Always set `call. = FALSE` when using `stop()` or `warning()` to enforce a secure-by-default boundary and prevent internal execution paths from being disclosed to the end user.
+
+## 2024-07-28 - Prevent Information Disclosure via Unvalidated Inputs
+**Vulnerability:** Publicly exported functions `icci()` and `vuongtest()` did not validate user inputs like `conf.level`, `nested`, and `adj`. Invalid inputs (e.g., `NA` or wrong types) bypassed top-level safeguards and triggered raw R errors deep inside internal logic (e.g., `if (nested)` failing with "missing value where TRUE/FALSE needed" or `qnorm` failing with "NaNs produced"), leaking internal execution contexts.
+**Learning:** Unvalidated arguments passed to exported functions can cause fatal errors deep in the codebase, bypassing `stop(..., call. = FALSE)` safeguards and exposing internal stack contexts to users.
+**Prevention:** Always strictly validate the type, length, and bounds of user inputs at the very beginning of exported functions and fail securely using `stop("...", call. = FALSE)`.
diff --git a/R/icci.R b/R/icci.R
index f22278a..ad97659 100644
--- a/R/icci.R
+++ b/R/icci.R
@@ -64,6 +64,9 @@
 #' @importFrom stats AIC var qnorm
 #' @export
 icci <- function(object1, object2, conf.level=.95, ll1=llcont, ll2=llcont) {
+  if (length(conf.level) != 1 || !is.numeric(conf.level) || is.na(conf.level) || conf.level <= 0 || conf.level >= 1) {
+    stop("conf.level must be a single numeric value strictly between 0 and 1.", call. = FALSE)
+  }
 
   ## check objects, issue warnings/errors, get classes/calls
   obinfo <- check.obj(object1, object2)
diff --git a/R/vuongtest.R b/R/vuongtest.R
index 2bdfbf6..d5cf3c5 100644
--- a/R/vuongtest.R
+++ b/R/vuongtest.R
@@ -97,6 +97,12 @@
 #' @importFrom methods slotNames
 #' @export
 vuongtest <- function(object1, object2, nested=FALSE, adj="none", ll1=llcont, ll2=llcont, score1=NULL, score2=NULL, vc1=vcov, vc2=vcov) {
+  if (length(nested) != 1 || !is.logical(nested) || is.na(nested)) {
+    stop("nested must be a single logical value (TRUE or FALSE).", call. = FALSE)
+  }
+  if (length(adj) != 1 || !is.character(adj) || is.na(adj) || !(adj %in% c("none", "aic", "bic"))) {
+    stop('adj must be a single character string: "none", "aic", or "bic".', call. = FALSE)
+  }
 
   ## check objects, issue warnings/errors, get classes/calls
   obinfo <- check.obj(object1, object2)