diff --git a/.github/workflows/CI-windows.yml b/.github/workflows/CI-windows.yml
index 84e520d34..e39718b29 100644
--- a/.github/workflows/CI-windows.yml
+++ b/.github/workflows/CI-windows.yml
@@ -26,7 +26,7 @@ jobs:
       # see https://www.pcre.org/original/changelog.txt
       PCRE_VERSION: 8.45
       # see https://github.com/Z3Prover/z3/releases:
-      Z3_VERSION: 4.8.10
+      Z3_VERSION: 4.8.15
 
     steps:
       - uses: actions/checkout@v2
diff --git a/.github/workflows/release-windows.yml b/.github/workflows/release-windows.yml
index b271ff8e6..841c3fe42 100644
--- a/.github/workflows/release-windows.yml
+++ b/.github/workflows/release-windows.yml
@@ -26,7 +26,7 @@ jobs:
       # see https://www.pcre.org/original/changelog.txt
       PCRE_VERSION: 8.45
       # see https://github.com/Z3Prover/z3/releases:
-      Z3_VERSION: 4.8.10
+      Z3_VERSION: 4.8.15
       QT_VERSION: 5.15.2
 
     steps: