diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index bd880e6..990959d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -483,7 +483,7 @@ jobs:
 
       - name: Cache ~/.cargo/bin (twiggy, cargo-component)
         id: cargo-bin-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: |
             ~/.cargo/bin/twiggy
@@ -602,7 +602,7 @@ jobs:
           key: tiktoken-parity-stable
 
       - name: Cache vocab blobs
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: ~/.cache/stringcheese-tokenizer-tiktoken
           # Bust the cache only when the hash constants in
@@ -676,7 +676,7 @@ jobs:
         # job has already run on this ref, the `cl100k_base.tiktoken`
         # blob is present and the bench's cl100k group produces
         # numbers; otherwise it soft-skips.
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: ~/.cache/stringcheese-tokenizer-tiktoken
           key: tiktoken-vocabs-${{ hashFiles('crates/stringcheese-tokenizer-tiktoken-conformance/src/variant.rs') }}
@@ -983,7 +983,7 @@ jobs:
           key: wasm-tokenizer-component-cl100k-stable
 
       - name: Cache cl100k vocab blob
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: ~/.cache/stringcheese-tokenizer-tiktoken
           # Bust the cache only when the hash constant in the
diff --git a/.github/workflows/fuzz-nightly.yml b/.github/workflows/fuzz-nightly.yml
index 690b123..068d069 100644
--- a/.github/workflows/fuzz-nightly.yml
+++ b/.github/workflows/fuzz-nightly.yml
@@ -94,7 +94,7 @@ jobs:
       # simpler than the split restore/save+run-id pattern, and sufficient for
       # v0.1. If we later need to preserve per-run historical corpora, revisit.
       - name: Restore and save fuzz corpus
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: fuzz/corpus/${{ matrix.target }}
           key: fuzz-corpus-${{ matrix.target }}