diff --git a/pyproject.toml b/pyproject.toml
index 2915149c..cfdc892e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -73,7 +73,7 @@ optional-dependencies.dev = [
     "sphinx-inline-tabs==2025.12.21.14",
     "sphinx-lint==1.0.2",
     "sphinx-pyproject==0.3.0",
-    "sphinx-substitution-extensions==2026.1.12",
+    "sphinx-substitution-extensions==2026.6.17",
     "sphinxcontrib-spelling==8.0.2",
     # ``sphinxcontrib-towncrier`` renders unreleased news fragments
     # into docs/source/unreleased.rst during Sphinx builds.
diff --git a/uv.lock b/uv.lock
index ed7003b3..19cd20f2 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1951,7 +1951,7 @@ wheels = [
 
 [[package]]
 name = "sphinx-substitution-extensions"
-version = "2026.1.12"
+version = "2026.6.17"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "beartype" },
@@ -1959,9 +1959,9 @@ dependencies = [
     { name = "myst-parser" },
     { name = "sphinx" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/ca/3e/a82aa5fed0d06161a89dc2f6971b160f837cad44f196c467fc6b2132acaa/sphinx_substitution_extensions-2026.1.12.tar.gz", hash = "sha256:25e0c6c40fbf9e1df593883da946879044a3bf8d85652c8c58f354a53575d736", size = 31676, upload-time = "2026-01-12T06:19:35.324Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/dd/fb/6bf1b3e5bbd97d6f4632e2bb8f48518f8400cf0e4d2949f15be5a933b068/sphinx_substitution_extensions-2026.6.17.tar.gz", hash = "sha256:b7901937a43853bdaa97408ab8d73c9dc3497ec9bcf3a0c4b5fb2cce8baece13", size = 37045, upload-time = "2026-06-17T09:57:31.943Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/9b/5e/9caa7167d2ef2b60326765150d64513be1b61b1864ad58a92683578b2776/sphinx_substitution_extensions-2026.1.12-py2.py3-none-any.whl", hash = "sha256:9152beb4f0f5cab52057681b376a473fa6b997defc85d4ac154dd12b13a3e987", size = 8766, upload-time = "2026-01-12T06:19:33.541Z" },
+    { url = "https://files.pythonhosted.org/packages/38/e9/b8f35529c3fa1fd3efd232113c5342bef4ab0cb703a1a3beda2fcccb6392/sphinx_substitution_extensions-2026.6.17-py2.py3-none-any.whl", hash = "sha256:9971b1e402d13faaca903af894130a831218f78e8e266d36cbcddad83b7f7609", size = 10152, upload-time = "2026-06-17T09:57:30.783Z" },
 ]
 
 [[package]]
@@ -2528,7 +2528,7 @@ requires-dist = [
     { name = "sphinx-inline-tabs", marker = "extra == 'dev'", specifier = "==2025.12.21.14" },
     { name = "sphinx-lint", marker = "extra == 'dev'", specifier = "==1.0.2" },
     { name = "sphinx-pyproject", marker = "extra == 'dev'", specifier = "==0.3.0" },
-    { name = "sphinx-substitution-extensions", marker = "extra == 'dev'", specifier = "==2026.1.12" },
+    { name = "sphinx-substitution-extensions", marker = "extra == 'dev'", specifier = "==2026.6.17" },
     { name = "sphinxcontrib-spelling", marker = "extra == 'dev'", specifier = "==8.0.2" },
     { name = "sphinxcontrib-towncrier", marker = "extra == 'dev'", specifier = "==0.5.0a0" },
     { name = "strict-kwargs", marker = "extra == 'dev'", specifier = "==2026.6.8.post1" },