diff --git a/dangerzone/isolation_provider/base.py b/dangerzone/isolation_provider/base.py
index e8c9d5c..6d4d3ff 100644
--- a/dangerzone/isolation_provider/base.py
+++ b/dangerzone/isolation_provider/base.py
@@ -45,9 +45,9 @@ def read_int(f: IO[bytes]) -> int:
 
 
 def read_debug_text(f: IO[bytes], size: int) -> str:
-    """Read arbitrarily long text (for debug purposes)"""
+    """Read arbitrarily long text (for debug purposes), and sanitize it."""
     untrusted_text = f.read(size).decode("ascii", errors="replace")
-    return replace_control_chars(untrusted_text)
+    return replace_control_chars(untrusted_text, keep_newlines=True)
 
 
 class IsolationProvider(ABC):
diff --git a/dangerzone/util.py b/dangerzone/util.py
index 5f25da0..b56a2e8 100644
--- a/dangerzone/util.py
+++ b/dangerzone/util.py
@@ -66,11 +66,14 @@ def get_subprocess_startupinfo():  # type: ignore [no-untyped-def]
         return None
 
 
-def replace_control_chars(untrusted_str: str) -> str:
+def replace_control_chars(untrusted_str: str, keep_newlines: bool = False) -> str:
     """Remove control characters from string. Protects a terminal emulator
     from obscure control characters.
 
     Control characters are replaced by � U+FFFD Replacement Character.
+
+    If a user wants to keep the newline character (e.g., because they are sanitizing a
+    multi-line text), they must pass `keep_newlines=True`.
     """
 
     def is_safe(chr: str) -> bool:
@@ -90,5 +93,8 @@ def replace_control_chars(untrusted_str: str) -> str:
 
     sanitized_str = ""
     for char in untrusted_str:
-        sanitized_str += char if is_safe(char) else "�"
+        if (keep_newlines and char == "\n") or is_safe(char):
+            sanitized_str += char
+        else:
+            sanitized_str += "�"
     return sanitized_str
diff --git a/tests/test_util.py b/tests/test_util.py
index 04eecb2..a4126f9 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -30,3 +30,8 @@ def test_replace_control_chars(uncommon_text: str, sanitized_text: str) -> None:
     assert util.replace_control_chars(uncommon_text) == sanitized_text
     assert util.replace_control_chars("normal text") == "normal text"
     assert util.replace_control_chars("") == ""
+    assert util.replace_control_chars("multi-line\ntext") == "multi-line�text"
+    assert (
+        util.replace_control_chars("multi-line\ntext", keep_newlines=True)
+        == "multi-line\ntext"
+    )