diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 575902643f..9678009651 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -139,6 +139,11 @@ jobs:
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
 
+      # The runner's system Python can be newer than PyO3 supports.
+      - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+        with:
+          python-version-file: .python-version
+
       - name: Install Rust Toolchain
         run: |
           rustup toolchain install stable --profile minimal --no-self-update
diff --git a/.python-version b/.python-version
index 44305e2f87..4de75f8d77 100644
--- a/.python-version
+++ b/.python-version
@@ -1 +1 @@
-3.13.12
+3.13.15
diff --git a/Dockerfile b/Dockerfile
index 0bb3148cb4..b6262e8264 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-ARG PYTHON_VERSION=3.13.12
+ARG PYTHON_VERSION=3.13.15
 
 FROM ghcr.io/getsentry/image-mirror-library-python:${PYTHON_VERSION}-slim-trixie AS build_base