diff --git a/.github/workflows/ci-doctor.lock.yml b/.github/workflows/ci-doctor.lock.yml
index 15915cdbe..4a58ea304 100644
--- a/.github/workflows/ci-doctor.lock.yml
+++ b/.github/workflows/ci-doctor.lock.yml
@@ -39,7 +39,7 @@ jobs:
         uses: actions/checkout@v6
       # Cache configuration from frontmatter processed below
       - name: Cache (investigation-memory-${{ github.repository }})
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           key: investigation-memory-${{ github.repository }}
           path: |
diff --git a/.github/workflows/ocaml.yaml b/.github/workflows/ocaml.yaml
index 7b328463b..255e258a3 100644
--- a/.github/workflows/ocaml.yaml
+++ b/.github/workflows/ocaml.yaml
@@ -21,7 +21,7 @@ jobs:
 
       # Cache ccache (shared across runs)
       - name: Cache ccache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/.ccache
           key: ${{ runner.os }}-ccache-${{ github.sha }}
@@ -30,7 +30,7 @@ jobs:
 
       # Cache opam (compiler + packages)
       - name: Cache opam
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/.opam
           key: ${{ runner.os }}-opam-${{ matrix.ocaml-version }}-${{ github.sha }}