diff --git a/.github/workflows/after-merge.yml b/.github/workflows/after-merge.yml
index c9a3b86d644..eed665bd8db 100644
--- a/.github/workflows/after-merge.yml
+++ b/.github/workflows/after-merge.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: ['16.x', '18.x']
+        node-version: ['16.x', '18.18']
     steps:
       - uses: actions/checkout@v3
         with:
@@ -38,7 +38,7 @@ jobs:
     strategy:
       matrix:
         # note: only use one node-version
-        node-version: ['18.x']
+        node-version: ['18.18']
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/restore-node
@@ -87,7 +87,7 @@ jobs:
     strategy:
       matrix:
         # note: only use one node-version
-        node-version: ['18.x']
+        node-version: ['18.18']
     if: ${{github.event_name == 'push' }}
     steps:
       - uses: actions/checkout@v3
@@ -131,7 +131,7 @@ jobs:
     strategy:
       matrix:
         # note: only use one node-version
-        node-version: ['18.x']
+        node-version: ['18.18']
     if: ${{github.event_name == 'push'}}
     steps:
       - uses: actions/checkout@v3
diff --git a/.github/workflows/ag-solo-xs.yml.DISABLED b/.github/workflows/ag-solo-xs.yml.DISABLED
index e832dd99453..c7bec05b8ab 100644
--- a/.github/workflows/ag-solo-xs.yml.DISABLED
+++ b/.github/workflows/ag-solo-xs.yml.DISABLED
@@ -19,7 +19,7 @@ jobs:
     - uses: actions/checkout@v3
     - uses: actions/setup-node@v3
       with:
-        node-version: '18.x'
+        node-version: '18.18'
     - name: cache node modules
       uses: actions/cache@v3
       with:
diff --git a/.github/workflows/benchmarks.yml b/.github/workflows/benchmarks.yml
index e89724538f1..066b4ac38ec 100644
--- a/.github/workflows/benchmarks.yml
+++ b/.github/workflows/benchmarks.yml
@@ -21,7 +21,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/restore-node
         with:
-          node-version: '18.x'
+          node-version: '18.18'
 
       - name: yarn bench (boot)
         shell: bash
diff --git a/.github/workflows/integration.yml b/.github/workflows/integration.yml
index 47c0193ef25..c20fb6a00be 100644
--- a/.github/workflows/integration.yml
+++ b/.github/workflows/integration.yml
@@ -61,7 +61,7 @@ jobs:
       # Prerequisites
       - uses: ./.github/actions/restore-node
         with:
-          node-version: 18.x
+          node-version: 18.18
           keep-endo: 'true'
 
       # Select a branch on dapp to test against by adding text to the body of the
@@ -130,7 +130,7 @@ jobs:
           path: ./agoric-sdk
       - uses: ./agoric-sdk/.github/actions/restore-node
         with:
-          node-version: 18.x
+          node-version: 18.18
           path: ./agoric-sdk
           # Forces xsnap to initialize all memory to random data, which increases
           # the chances the content of snapshots may deviate between validators
diff --git a/.github/workflows/test-all-packages.yml b/.github/workflows/test-all-packages.yml
index 2fbbbd5af0e..916ceb475f6 100644
--- a/.github/workflows/test-all-packages.yml
+++ b/.github/workflows/test-all-packages.yml
@@ -31,7 +31,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: ['16.x', '18.x']
+        node-version: ['16.x', '18.18']
     steps:
       - uses: actions/checkout@v3
         with:
@@ -64,7 +64,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/restore-node
         with:
-          node-version: '18.x'
+          node-version: '18.18'
 
       # first job also does repo-level linting
       - name: lint repo format
@@ -84,7 +84,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/restore-node
         with:
-          node-version: '18.x'
+          node-version: '18.18'
 
       - name: yarn lint rest
         run: ./scripts/lint-with-types.sh rest
@@ -98,12 +98,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
 
@@ -189,12 +189,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
       - uses: actions/checkout@v3
@@ -306,12 +306,12 @@ jobs:
     strategy:
       matrix:
         # test:xs is noop in solo/package.json
-        engine: ['16.x', '18.x']
+        engine: ['16.x', '18.18']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
 
@@ -347,12 +347,12 @@ jobs:
     strategy:
       matrix:
         # test:xs is noop in cosmic-swingset/package.json
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
 
@@ -391,12 +391,12 @@ jobs:
     strategy:
       matrix:
         # test:xs is noop in inter-protocol/package.json
-        engine: ['16.x', '18.x']
+        engine: ['16.x', '18.18']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
 
@@ -431,12 +431,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
 
@@ -472,12 +472,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
 
@@ -514,12 +514,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
 
@@ -566,12 +566,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
       - uses: actions/checkout@v3
@@ -607,12 +607,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs' || 'test' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
       - uses: actions/checkout@v3
@@ -649,13 +649,13 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         # END-TEST-BOILERPLATE
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs-unit' || 'test:unit' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
         # BEGIN-TEST-BOILERPLATE
@@ -691,13 +691,13 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        engine: ['16.x', '18.x', 'xs']
+        engine: ['16.x', '18.18', 'xs']
     steps:
       - name: set vars
         id: vars
         # END-TEST-BOILERPLATE
         run: |
-          echo "node-version=${{ matrix.engine == 'xs' && '18.x' || matrix.engine }}" >> $GITHUB_OUTPUT
+          echo "node-version=${{ matrix.engine == 'xs' && '18.18' || matrix.engine }}" >> $GITHUB_OUTPUT
           echo "test=${{ matrix.engine == 'xs' && 'test:xs-worker' || 'test:swingset' }}" >> $GITHUB_OUTPUT
           echo "GH_ENGINE=${{ matrix.engine }}" >> $GITHUB_ENV
         # BEGIN-TEST-BOILERPLATE