From 62a9e787edb2cfce9858fa4ceda5461680efc590 Mon Sep 17 00:00:00 2001
From: akallabeth <akallabeth@posteo.net>
Date: Sat, 10 Jan 2026 08:31:07 +0100
Subject: [PATCH] [crypto,base64] ensure char is singend

---
 libfreerdp/crypto/base64.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libfreerdp/crypto/base64.c b/libfreerdp/crypto/base64.c
index 091e9a7e2..68ad3f076 100644
--- a/libfreerdp/crypto/base64.c
+++ b/libfreerdp/crypto/base64.c
@@ -400,7 +400,8 @@ static inline char* base64_encode(const BYTE* WINPR_RESTRICT alphabet,
 
 static inline int base64_decode_char(const signed char* WINPR_RESTRICT alphabet, char c)
 {
-	if (c <= '\0')
+	/* ensure char is signed for this check */
+	if ((int)c <= '\0')
 		return -1;
 
 	return alphabet[(size_t)c];