diff --git a/.github/workflows/ubuntu20-sani.yml b/.github/workflows/ubuntu20-sani.yml
index 36eef71e0..2e3cc3f71 100644
--- a/.github/workflows/ubuntu20-sani.yml
+++ b/.github/workflows/ubuntu20-sani.yml
@@ -3,7 +3,7 @@ name: Ubuntu 20.04 CI (GCC 9) With Memory Sanitizer
 on: [push, pull_request]
 
 jobs:
-  ubuntu-build:
+  ubuntu-build-address-sanitizier:
     if: >-
       ! contains(toJSON(github.event.commits.*.message), '[skip ci]') &&
       ! contains(toJSON(github.event.commits.*.message), '[skip github]')
@@ -21,6 +21,18 @@ jobs:
           cmake -DSIMDJSON_SANITIZE=ON -DCMAKE_BUILD_TYPE=Debug -DSIMDJSON_GOOGLE_BENCHMARKS=OFF -DSIMDJSON_DEVELOPER_MODE=ON -DBUILD_SHARED_LIBS=OFF ..  &&
           cmake --build .   &&
           ctest --output-on-failure -LE explicitonly -j
+  ubuntu-build-undefined-sanitizer:
+    if: >-
+      ! contains(toJSON(github.event.commits.*.message), '[skip ci]') &&
+      ! contains(toJSON(github.event.commits.*.message), '[skip github]')
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/cache@v3
+        with:
+          path: dependencies/.cache
+          key: ${{ hashFiles('dependencies/CMakeLists.txt') }}
+          ctest --output-on-failure -LE explicitonly -j
       - name: Use cmake with undefined sanitizer
         run: |
           mkdir builddebugundefsani &&