diff --git a/nixos/tests/ceph-multi-node-bluestore.nix b/nixos/tests/ceph-multi-node-bluestore.nix
index 96fefca78230..a4e7b8fd047a 100644
--- a/nixos/tests/ceph-multi-node-bluestore.nix
+++ b/nixos/tests/ceph-multi-node-bluestore.nix
@@ -209,6 +209,11 @@ let
         vlans = [ 1 ];
       };
 
+      # Ceph 20.2.4 introduced the aes256k cipher for authentication.
+      # Linux started supporting these in kernel version 7.0.
+      # Remove this line at the earliest convenience (i.e. when tests are run by 7.0 or higher by default).
+      boot.kernelPackages = pkgs.linuxPackages_latest;
+
       networking = networkConfig;
 
       environment.systemPackages = with pkgs; [
diff --git a/nixos/tests/ceph-multi-node-deprecated-filestore.nix b/nixos/tests/ceph-multi-node-deprecated-filestore.nix
index 992a74f72972..f0705dece1ae 100644
--- a/nixos/tests/ceph-multi-node-deprecated-filestore.nix
+++ b/nixos/tests/ceph-multi-node-deprecated-filestore.nix
@@ -47,6 +47,11 @@ let
         vlans = [ 1 ];
       };
 
+      # Ceph 20.2.4 introduced the aes256k cipher for authentication.
+      # Linux started supporting these in kernel version 7.0.
+      # Remove this line at the earliest convenience (i.e. when tests are run by 7.0 or higher by default).
+      boot.kernelPackages = pkgs.linuxPackages_latest;
+
       networking = networkConfig;
 
       environment.systemPackages = with pkgs; [
diff --git a/nixos/tests/ceph-single-node-bluestore-dmcrypt.nix b/nixos/tests/ceph-single-node-bluestore-dmcrypt.nix
index 8ab8cbba3a62..a5782abbc7c8 100644
--- a/nixos/tests/ceph-single-node-bluestore-dmcrypt.nix
+++ b/nixos/tests/ceph-single-node-bluestore-dmcrypt.nix
@@ -34,6 +34,11 @@ in
         20480
       ];
 
+      # Ceph 20.2.4 introduced the aes256k cipher for authentication.
+      # Linux started supporting these in kernel version 7.0.
+      # Remove this line at the earliest convenience (i.e. when tests are run by 7.0 or higher by default).
+      boot.kernelPackages = pkgs.linuxPackages_latest;
+
       # networking setup (no external connectivity required, only local IPv6)
       networking.useDHCP = false;
       systemd.network = {
diff --git a/nixos/tests/ceph-single-node-bluestore.nix b/nixos/tests/ceph-single-node-bluestore.nix
index 5e84695ac4be..fac0b797683b 100644
--- a/nixos/tests/ceph-single-node-bluestore.nix
+++ b/nixos/tests/ceph-single-node-bluestore.nix
@@ -48,6 +48,11 @@ let
         vlans = [ 1 ];
       };
 
+      # Ceph 20.2.4 introduced the aes256k cipher for authentication.
+      # Linux started supporting these in kernel version 7.0.
+      # Remove this line at the earliest convenience (i.e. when tests are run by 7.0 or higher by default).
+      boot.kernelPackages = pkgs.linuxPackages_latest;
+
       networking = networkConfig;
 
       environment.systemPackages = with pkgs; [
diff --git a/nixos/tests/ceph-single-node-deprecated-filestore.nix b/nixos/tests/ceph-single-node-deprecated-filestore.nix
index c08238559155..908760bebfd8 100644
--- a/nixos/tests/ceph-single-node-deprecated-filestore.nix
+++ b/nixos/tests/ceph-single-node-deprecated-filestore.nix
@@ -52,6 +52,11 @@ let
         vlans = [ 1 ];
       };
 
+      # Ceph 20.2.4 introduced the aes256k cipher for authentication.
+      # Linux started supporting these in kernel version 7.0.
+      # Remove this line at the earliest convenience (i.e. when tests are run by 7.0 or higher by default).
+      boot.kernelPackages = pkgs.linuxPackages_latest;
+
       networking = networkConfig;
 
       environment.systemPackages = with pkgs; [