diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b241eeb32..95551d61f 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -23,7 +23,7 @@ repos:
     hooks:
       - id: validate-pyproject
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: "v0.12.3"
+    rev: "v0.12.4"
     hooks:
       - id: ruff-format
       - id: ruff
diff --git a/src/tox/config/source/ini.py b/src/tox/config/source/ini.py
index 90dd40f53..bee5bc72c 100644
--- a/src/tox/config/source/ini.py
+++ b/src/tox/config/source/ini.py
@@ -32,7 +32,7 @@ def __init__(self, path: Path, content: str | None = None) -> None:
         if content is None:
             if not path.exists():
                 raise ValueError
-            content = path.read_text()
+            content = path.read_text(encoding="utf-8")
         self._parser.read_string(content, str(path))
         self._section_mapping: defaultdict[str, list[str]] = defaultdict(list)
 
diff --git a/tests/execute/local_subprocess/bad_process.py b/tests/execute/local_subprocess/bad_process.py
index 395500020..72b18aa2f 100644
--- a/tests/execute/local_subprocess/bad_process.py
+++ b/tests/execute/local_subprocess/bad_process.py
@@ -32,7 +32,7 @@ def _p(m: str) -> None:
 try:
     start_file = Path(sys.argv[1])
     _p(f"create {start_file}")
-    start_file.write_text("")
+    start_file.write_text("", encoding="utf-8")
     _p(f"created {start_file}")
     while True:
         time.sleep(0.01)