diff --git a/.github/workflows/native_release.yml b/.github/workflows/native_release.yml
index 73e595f..ac10725 100644
--- a/.github/workflows/native_release.yml
+++ b/.github/workflows/native_release.yml
@@ -32,8 +32,8 @@ jobs:
           - { target: ios-arm64-sim, runs_on: macos-latest }
           - { target: ios-x64-sim, runs_on: macos-latest }
           - { target: android-arm64, runs_on: ubuntu-latest }
-          - { target: linux-x64, runs_on: ubuntu-latest, smoke: "--expect-device CPU" }
-          - { target: linux-x64-vulkan, runs_on: ubuntu-latest, smoke: "--expect-device Vulkan" }
+          - { target: linux-x64, runs_on: ubuntu-24.04, smoke: "--expect-device CPU" }
+          - { target: linux-x64-vulkan, runs_on: ubuntu-24.04, smoke: "--expect-device Vulkan" }
           - { target: linux-arm64, runs_on: ubuntu-24.04-arm, smoke: "--expect-device CPU" }
           - { target: linux-arm64-vulkan, runs_on: ubuntu-24.04-arm, smoke: "--expect-device Vulkan" }
           - { target: windows-x64, runs_on: windows-2022, smoke: "--expect-device CPU" }
diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index 80c609b..f1d5eec 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -93,8 +93,8 @@ jobs:
           - { target: ios-arm64-sim, runs_on: macos-latest }
           - { target: ios-x64-sim, runs_on: macos-latest }
           - { target: android-arm64, runs_on: ubuntu-latest }
-          - { target: linux-x64, runs_on: ubuntu-latest, smoke: "--expect-device CPU" }
-          - { target: linux-x64-vulkan, runs_on: ubuntu-latest, smoke: "--expect-device Vulkan" }
+          - { target: linux-x64, runs_on: ubuntu-24.04, smoke: "--expect-device CPU" }
+          - { target: linux-x64-vulkan, runs_on: ubuntu-24.04, smoke: "--expect-device Vulkan" }
           - { target: windows-x64, runs_on: windows-2022, smoke: "--expect-device CPU" }
           - { target: windows-x64-vulkan, runs_on: windows-2022, smoke: "--expect-device CPU" }
     steps:
diff --git a/tests/test_release_workflow.py b/tests/test_release_workflow.py
index 0c39158..668a71b 100644
--- a/tests/test_release_workflow.py
+++ b/tests/test_release_workflow.py
@@ -23,6 +23,18 @@ def test_preparation_has_no_release_write_path(self):
         self.assertIn("      contents: write\n", job_header)
         self.assertEqual(workflow.count("action-gh-release@"), 1)
 
+    def test_linux_runtime_builds_keep_the_qualified_ubuntu_baseline(self):
+        # The floating label moved to Ubuntu 26.04 and a different software
+        # Vulkan matrix path; qualification and release must use one baseline.
+        for name in ("validate.yml", "native_release.yml"):
+            workflow = (ROOT / ".github/workflows" / name).read_text()
+            for target in ("linux-x64", "linux-x64-vulkan"):
+                with self.subTest(workflow=name, target=target):
+                    self.assertRegex(
+                        workflow,
+                        rf"target: {target}, runs_on: ubuntu-24\.04,",
+                    )
+
     def test_normal_release_mode_remains_explicit_and_enabled(self):
         workflow = (ROOT / ".github/workflows/native_release.yml").read_text()
         self.assertIn(