diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6512a286b..902deec30 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 - core: fix integer overflow in function util_version_number
 - core: fix buffer overflow in function util_parse_time
 - core: fix buffer overflow in function eval_syntax_highlight_colorize
+- core: fix buffer overflow in function eval_string_base_encode
 - core: fix memory leak in function util_parse_delay
 
 ## Version 4.6.2 (2025-04-18)
diff --git a/src/core/core-eval.c b/src/core/core-eval.c
index bfd8ee890..329553115 100644
--- a/src/core/core-eval.c
+++ b/src/core/core-eval.c
@@ -894,7 +894,7 @@ eval_string_base_encode (const char *text)
 
     ptr_string++;
     length = strlen (ptr_string);
-    result = malloc ((length * 4) + 1);
+    result = malloc ((length * 4) + 8 + 1);
     if (!result)
         goto end;