diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 173b342eac..5b1d28fafd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -71,10 +71,10 @@ jobs:
         include:
           # Currently used Rust version, same as in `rust-toolchain` file.
           - os: ubuntu-latest
-            rust: 1.65.0
+            rust: 1.64.0
             python: 3.9
           - os: windows-latest
-            rust: 1.65.0
+            rust: 1.64.0
             python: false # Python bindings compilation on Windows is not supported.
 
           # Minimum Supported Rust Version = 1.61.0
diff --git a/rust-toolchain b/rust-toolchain
index 902c74186f..9405730420 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-1.65.0
+1.64.0
diff --git a/scripts/coredeps/install-rust.sh b/scripts/coredeps/install-rust.sh
index dcbf30b77f..b4a08f3f10 100755
--- a/scripts/coredeps/install-rust.sh
+++ b/scripts/coredeps/install-rust.sh
@@ -7,7 +7,7 @@ set -euo pipefail
 #
 # Avoid using rustup here as it depends on reading /proc/self/exe and
 # has problems running under QEMU.
-RUST_VERSION=1.65.0
+RUST_VERSION=1.64.0
 
 ARCH="$(uname -m)"
 test -f "/lib/libc.musl-$ARCH.so.1" && LIBC=musl || LIBC=gnu