diff --git a/.github/workflows/test-build.yml b/.github/workflows/test-build.yml
index 4ba527e58..43b8e7cb9 100644
--- a/.github/workflows/test-build.yml
+++ b/.github/workflows/test-build.yml
@@ -33,6 +33,12 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      # StarSling Linux runners (vars.CI_LINUX_RUNNER) preinstall rustc 1.92, older
+      # than GitHub's ubuntu-24.04 image (1.99); 1.92 cannot compile the
+      # broker (stable-only atomic try_update). Install the toolchain explicitly.
+      - name: Setup Rust toolchain
+        uses: dtolnay/rust-toolchain@4360b52568e2003a75bf9bc1d59f33a8e3fc893c # stable
+
       - name: Setup Bun
         uses: oven-sh/setup-bun@v2
         with:
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 1aaf102c9..27c1ecf2d 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -40,6 +40,12 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      # StarSling Linux runners (vars.CI_LINUX_RUNNER) preinstall rustc 1.92, older
+      # than GitHub's ubuntu-24.04 image (1.99); 1.92 cannot compile the
+      # broker (stable-only atomic try_update). Install the toolchain explicitly.
+      - name: Setup Rust toolchain
+        uses: dtolnay/rust-toolchain@4360b52568e2003a75bf9bc1d59f33a8e3fc893c # stable
+
       - name: Setup Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v4
         with:
@@ -148,6 +154,12 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      # StarSling Linux runners (vars.CI_LINUX_RUNNER) preinstall rustc 1.92, older
+      # than GitHub's ubuntu-24.04 image (1.99); 1.92 cannot compile the
+      # broker (stable-only atomic try_update). Install the toolchain explicitly.
+      - name: Setup Rust toolchain
+        uses: dtolnay/rust-toolchain@4360b52568e2003a75bf9bc1d59f33a8e3fc893c # stable
+
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with: