diff --git a/cmake_targets/tools/build_helper b/cmake_targets/tools/build_helper
index 7806ee999b..d03bd31b56 100755
--- a/cmake_targets/tools/build_helper
+++ b/cmake_targets/tools/build_helper
@@ -32,7 +32,7 @@ OS_DISTRO=$(grep "^ID=" /etc/os-release | sed "s/ID=//" | sed "s/\"//g")
 OS_RELEASE=$(grep "^VERSION_ID=" /etc/os-release | sed "s/VERSION_ID=//" | sed "s/\"//g")
 case "$OS_DISTRO" in
   fedora) OS_BASEDISTRO="fedora"; INSTALLER="dnf"; CMAKE="cmake" ;;
-  rhel)   OS_BASEDISTRO="fedora"; INSTALLER="yum"; CMAKE="cmake3" ;;
+  rhel)   OS_BASEDISTRO="fedora"; INSTALLER="dnf"; CMAKE="cmake3" ;;
   rocky)  OS_BASEDISTRO="fedora"; INSTALLER="dnf"; CMAKE="cmake" ;;
   centos) OS_BASEDISTRO="centos"; INSTALLER="yum"; CMAKE="cmake3" ;;
   debian) OS_BASEDISTRO="debian"; INSTALLER="apt-get"; CMAKE="cmake" ;;
diff --git a/docker/Dockerfile.base.rhel9 b/docker/Dockerfile.base.rhel9
index aa7d96c348..d8e1ff92ae 100644
--- a/docker/Dockerfile.base.rhel9
+++ b/docker/Dockerfile.base.rhel9
@@ -42,11 +42,11 @@ COPY ./rhsm-ca /etc/rhsm/ca
 ENV SMDEV_CONTAINER_OFF=1
 #install developers pkg/repo
 RUN rm -f /etc/rhsm-host && \
-    yum repolist --disablerepo=* && \
+    dnf repolist --disablerepo=* && \
     subscription-manager repos --enable codeready-builder-for-rhel-9-x86_64-rpms && \
     dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm -y && \
-    yum update -y && \
-    yum install -y \
+    dnf update -y && \
+    dnf install -y \
        #gcc needed for build_oai
        gcc gcc-c++ \ 
        diffutils \
diff --git a/docker/Dockerfile.clang.rhel9 b/docker/Dockerfile.clang.rhel9
index d548fbe674..fccef45eec 100644
--- a/docker/Dockerfile.clang.rhel9
+++ b/docker/Dockerfile.clang.rhel9
@@ -32,7 +32,7 @@ WORKDIR /oai-ran
 COPY . .
 
 #only install LLVM (clang, ...) for this container, the others don't need it
-RUN yum install -y llvm-toolset
+RUN dnf install -y llvm-toolset
 
 #run build_oai to build the target image
 RUN /bin/sh oaienv && \
diff --git a/docker/Dockerfile.eNB.rhel9 b/docker/Dockerfile.eNB.rhel9
index 042f364988..2a630d9669 100644
--- a/docker/Dockerfile.eNB.rhel9
+++ b/docker/Dockerfile.eNB.rhel9
@@ -36,8 +36,8 @@ RUN python3 ./docker/scripts/generateTemplate.py ./docker/scripts/enb_parameters
 FROM registry.access.redhat.com/ubi9/ubi:latest as oai-enb
 ENV TZ=Europe/Paris
 
-RUN yum update -y && \
-    yum install -y --enablerepo="ubi-9-codeready-builder" \
+RUN dnf update -y && \
+    dnf install -y --enablerepo="ubi-9-codeready-builder" \
         lksctp-tools \
         tzdata \
         procps-ng \
diff --git a/docker/Dockerfile.gNB.aw2s.rhel9 b/docker/Dockerfile.gNB.aw2s.rhel9
index a701e29012..ee76d6d707 100644
--- a/docker/Dockerfile.gNB.aw2s.rhel9
+++ b/docker/Dockerfile.gNB.aw2s.rhel9
@@ -41,9 +41,9 @@ RUN /bin/sh oaienv && \
 FROM registry.access.redhat.com/ubi9/ubi:latest as oai-gnb-aw2s
 ENV TZ=Europe/Paris
 
-RUN yum repolist --disablerepo=* && \
-    yum update -y && \
-    yum install -y --enablerepo="ubi-9-codeready-builder" \
+RUN dnf repolist --disablerepo=* && \
+    dnf update -y && \
+    dnf install -y --enablerepo="ubi-9-codeready-builder" \
         procps-ng \
         libXpm \
         libX11 \
diff --git a/docker/Dockerfile.gNB.rhel9 b/docker/Dockerfile.gNB.rhel9
index bcfd042c27..e99b9b3e95 100644
--- a/docker/Dockerfile.gNB.rhel9
+++ b/docker/Dockerfile.gNB.rhel9
@@ -36,9 +36,9 @@ RUN python3 ./docker/scripts/generateTemplate.py ./docker/scripts/gnb_parameters
 FROM registry.access.redhat.com/ubi9/ubi:latest as oai-gnb
 ENV TZ=Europe/Paris
 
-RUN yum repolist --disablerepo=* && \
-    yum update -y && \
-    yum install -y --enablerepo="ubi-9-codeready-builder" \
+RUN dnf repolist --disablerepo=* && \
+    dnf update -y && \
+    dnf install -y --enablerepo="ubi-9-codeready-builder" \
         procps-ng \
         libXpm \
         libX11 \
diff --git a/docker/Dockerfile.lteRU.rhel9 b/docker/Dockerfile.lteRU.rhel9
index 8061d96286..fede7c62a3 100644
--- a/docker/Dockerfile.lteRU.rhel9
+++ b/docker/Dockerfile.lteRU.rhel9
@@ -36,8 +36,8 @@ RUN python3 ./docker/scripts/generateTemplate.py ./docker/scripts/enb_parameters
 FROM registry.access.redhat.com/ubi9/ubi:latest as oai-lte-ru
 ENV TZ=Europe/Paris
 
-RUN yum update -y && \
-    yum install -y --enablerepo="ubi-9-codeready-builder" \
+RUN dnf update -y && \
+    dnf install -y --enablerepo="ubi-9-codeready-builder" \
         tzdata \
         procps-ng \
         atlas \
diff --git a/docker/Dockerfile.lteUE.rhel9 b/docker/Dockerfile.lteUE.rhel9
index 19b5f6f818..aa421f47a6 100644
--- a/docker/Dockerfile.lteUE.rhel9
+++ b/docker/Dockerfile.lteUE.rhel9
@@ -37,8 +37,8 @@ RUN python3 ./docker/scripts/generateTemplate.py ./docker/scripts/lte_ue_paramet
 FROM registry.access.redhat.com/ubi9/ubi:latest as oai-lte-ue
 ENV TZ=Europe/Paris
 
-RUN yum update -y && \
-    yum install -y --enablerepo="ubi-9-codeready-builder" \
+RUN dnf update -y && \
+    dnf install -y --enablerepo="ubi-9-codeready-builder" \
         lksctp-tools \
         procps-ng \
         tzdata \
diff --git a/docker/Dockerfile.nrUE.rhel9 b/docker/Dockerfile.nrUE.rhel9
index a254db7b06..6c3976b2c8 100644
--- a/docker/Dockerfile.nrUE.rhel9
+++ b/docker/Dockerfile.nrUE.rhel9
@@ -36,8 +36,8 @@ RUN python3 ./docker/scripts/generateTemplate.py ./docker/scripts/nr_ue_paramete
 FROM registry.access.redhat.com/ubi9/ubi:latest as oai-nr-ue
 ENV TZ=Europe/Paris
 
-RUN yum update -y && \
-    yum install -y --enablerepo="ubi-9-codeready-builder" \
+RUN dnf update -y && \
+    dnf install -y --enablerepo="ubi-9-codeready-builder" \
         lksctp-tools \
         procps-ng \
         tzdata \
diff --git a/docker/Dockerfile.phySim.rhel9 b/docker/Dockerfile.phySim.rhel9
index 8ad4cefe56..db063e3a8d 100644
--- a/docker/Dockerfile.phySim.rhel9
+++ b/docker/Dockerfile.phySim.rhel9
@@ -32,7 +32,7 @@ WORKDIR /oai-ran
 COPY . .
 
 #only install address and undefined behavior sanitizer for this container, the others don't need it
-RUN yum install -y libasan libubsan
+RUN dnf install -y libasan libubsan
 
 #run build_oai to build the target image
 RUN /bin/sh oaienv && \ 
@@ -43,8 +43,8 @@ RUN /bin/sh oaienv && \
 #start from scratch for target executable
 FROM registry.access.redhat.com/ubi9/ubi:latest as oai-physim
 
-RUN yum update -y && \
-    yum install -y --enablerepo="ubi-9-codeready-builder" \
+RUN dnf update -y && \
+    dnf install -y --enablerepo="ubi-9-codeready-builder" \
         lksctp-tools \
         tzdata \
         atlas \