diff --git a/.github/workflows/build-binaries.yml b/.github/workflows/build-binaries.yml
index 41ccf97..e9e1c7d 100644
--- a/.github/workflows/build-binaries.yml
+++ b/.github/workflows/build-binaries.yml
@@ -61,7 +61,7 @@ jobs:
           git reset --hard
           git clean -fdx
           # Work around flate2 1.1.6 ambiguity issues by pinning to a fixed release.
-          cargo +nightly-2025-09-14 update -p flate2 --precise 1.1.9
+          cargo +nightly-2025-09-14 update -p flate2 --precise 1.1.5
           cargo +nightly-2025-09-14 build --features testing --bins
       - name: Package binaries
         run: |