From 87c44759a8fcc27bbcae7592ebb3e2b2fddb8ec8 Mon Sep 17 00:00:00 2001
From: Andrew Chen <48723787+chuenchen309@users.noreply.github.com>
Date: Fri, 17 Jul 2026 09:06:33 +0800
Subject: [PATCH 1/2] fix(route): don't let a splat catchall match paths
 sharing its prefix

The catchall segment compiled to a bare `.*` with no separator, so
`posts/[[...splat]]` became `^/posts.*/?$` and matched `/postsomething`.
The frontend maps the same route to React Router's `posts/*`, which
matches the route and its descendants only, so a request could resolve
to a different page's on_load events than the page actually rendered.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 reflex/route.py           |  4 +++-
 tests/units/test_route.py | 19 ++++++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/reflex/route.py b/reflex/route.py
index 4b450fb6e25..bb3dbb53aae 100644
--- a/reflex/route.py
+++ b/reflex/route.py
@@ -172,7 +172,9 @@ def get_route_regex(keyworded_route: str) -> re.Pattern:
             # Match a single optional segment (/slug or nothing)
             regex_parts.append(r"(/[^/]+)?")
         elif part == constants.RouteRegex.DOUBLE_CATCHALL_SEGMENT:
-            regex_parts.append(".*")
+            # The frontend compiles this to React Router's `*`, which matches the
+            # route and its descendants only, so the segment separator is required.
+            regex_parts.append("(/.*)?")
         else:
             regex_parts.append(re.escape("/" + part))
     # Join the regex parts and compile the regex
diff --git a/tests/units/test_route.py b/tests/units/test_route.py
index fb3f37ef356..ae1b81e89cb 100644
--- a/tests/units/test_route.py
+++ b/tests/units/test_route.py
@@ -3,7 +3,7 @@
 from reflex_base import constants
 
 from reflex.app import App
-from reflex.route import get_route_args, verify_route_validity
+from reflex.route import get_route_args, get_router, verify_route_validity
 
 
 @pytest.mark.parametrize(
@@ -110,3 +110,20 @@ def test_check_routes_conflict_valid(mocker: MockerFixture, app, route1, route2)
     mocker.patch.object(app, "_pages", {route1: []})
     # test that running this does not throw an error.
     app._check_routes_conflict(route2)
+
+
+@pytest.mark.parametrize(
+    ("path", "expected"),
+    [
+        ("/posts", "posts/[[...splat]]"),
+        ("/posts/", "posts/[[...splat]]"),
+        ("/posts/2024/hello", "posts/[[...splat]]"),
+        ("/postsomething", None),
+        ("/posts-archive", None),
+    ],
+)
+def test_get_router_splat_catchall(path: str, expected: str | None):
+    # The frontend maps [[...splat]] to React Router's `posts/*`, which matches
+    # the route and its descendants but not paths that merely share the prefix.
+    router = get_router(["posts/[[...splat]]"])
+    assert router(path) == expected

From 3f7e7bb9b6e8c5c35e1acefe19d6723909763e7f Mon Sep 17 00:00:00 2001
From: Andrew Chen <48723787+chuenchen309@users.noreply.github.com>
Date: Fri, 17 Jul 2026 09:08:27 +0800
Subject: [PATCH 2/2] Add changelog fragment for #6790

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 news/6790.bugfix.md | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 news/6790.bugfix.md

diff --git a/news/6790.bugfix.md b/news/6790.bugfix.md
new file mode 100644
index 00000000000..df9738b98fb
--- /dev/null
+++ b/news/6790.bugfix.md
@@ -0,0 +1 @@
+A `[[...splat]]` catchall route no longer matches paths that merely share its prefix — `posts/[[...splat]]` matched `/postsomething` as well as `/posts` and its descendants, so the wrong page's `on_load` events could fire.