diff --git a/Dependencies.txt b/Dependencies.txt
index af2b32d937..cf704d33bf 100644
--- a/Dependencies.txt
+++ b/Dependencies.txt
@@ -1,4 +1,4 @@
-Protobuf=3.15.3
+Protobuf=3.15.7
 abseil-cpp=20200923.3
 Cbc=2.10.5
 Cgl=0.60.3
diff --git a/WORKSPACE b/WORKSPACE
index 919901137e..b8e91cc542 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -29,7 +29,7 @@ http_archive(
 # Protobuf
 git_repository(
     name = "com_google_protobuf",
-    commit = "983d115",  # release v3.15.3
+    commit = "878be35",  # release v3.15.7
     remote = "https://github.com/protocolbuffers/protobuf.git",
 )
 
diff --git a/cmake/dependencies/CMakeLists.txt b/cmake/dependencies/CMakeLists.txt
index ad557cfa1b..95ac9358dd 100644
--- a/cmake/dependencies/CMakeLists.txt
+++ b/cmake/dependencies/CMakeLists.txt
@@ -114,17 +114,17 @@ if(BUILD_Protobuf)
     FetchContent_Declare(
       protobuf
       GIT_REPOSITORY "https://github.com/protocolbuffers/protobuf.git"
-      GIT_TAG "v3.15.3"
+      GIT_TAG "v3.15.7"
       GIT_SUBMODULES ""
-      PATCH_COMMAND git apply "${CMAKE_CURRENT_LIST_DIR}/../../patches/protobuf-v3.15.3.patch"
+      PATCH_COMMAND git apply "${CMAKE_CURRENT_LIST_DIR}/../../patches/protobuf-v3.15.7.patch"
       SOURCE_SUBDIR cmake)
     FetchContent_MakeAvailable(protobuf)
   else()
     fetch_git_dependency(
       NAME Protobuf
       REPOSITORY "https://github.com/protocolbuffers/protobuf.git"
-      TAG "v3.15.3"
-      PATCH_COMMAND "git apply \"${CMAKE_CURRENT_LIST_DIR}/../../patches/protobuf-v3.15.3.patch\""
+      TAG "v3.15.7"
+      PATCH_COMMAND "git apply \"${CMAKE_CURRENT_LIST_DIR}/../../patches/protobuf-v3.15.7.patch\""
       SOURCE_SUBDIR cmake
       )
   endif()
diff --git a/cmake/host.CMakeLists.txt b/cmake/host.CMakeLists.txt
index d86ccdc1c4..c3b770c405 100644
--- a/cmake/host.CMakeLists.txt
+++ b/cmake/host.CMakeLists.txt
@@ -106,17 +106,17 @@ if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.18")
   FetchContent_Declare(
       protobuf
       GIT_REPOSITORY "https://github.com/protocolbuffers/protobuf.git"
-      GIT_TAG "v3.15.3"
+      GIT_TAG "v3.15.7"
       GIT_SUBMODULES ""
-      PATCH_COMMAND git apply "${CMAKE_CURRENT_LIST_DIR}/../../../patches/protobuf-v3.15.3.patch"
+      PATCH_COMMAND git apply "${CMAKE_CURRENT_LIST_DIR}/../../../patches/protobuf-v3.15.7.patch"
       SOURCE_SUBDIR cmake)
   FetchContent_MakeAvailable(protobuf)
 else()
   fetch_git_dependency(
       NAME Protobuf
       REPOSITORY "https://github.com/protocolbuffers/protobuf.git"
-      TAG "v3.15.3"
-      PATCH_COMMAND "git apply \"${CMAKE_CURRENT_LIST_DIR}/../../../patches/protobuf-v3.15.3.patch\""
+      TAG "v3.15.7"
+      PATCH_COMMAND "git apply \"${CMAKE_CURRENT_LIST_DIR}/../../../patches/protobuf-v3.15.7.patch\""
       SOURCE_SUBDIR cmake)
 endif()
 list(POP_BACK CMAKE_MESSAGE_INDENT)
diff --git a/makefiles/Makefile.third_party.unix.mk b/makefiles/Makefile.third_party.unix.mk
index 48b694c2ee..10a8a30b52 100644
--- a/makefiles/Makefile.third_party.unix.mk
+++ b/makefiles/Makefile.third_party.unix.mk
@@ -20,7 +20,7 @@ UNIX_SWIG_BINARY ?= swig
 PROTOC_BINARY := $(shell $(WHICH) ${UNIX_PROTOC_BINARY})
 
 # Tags of dependencies to checkout.
-PROTOBUF_TAG = v3.15.3
+PROTOBUF_TAG = v3.15.7
 ABSL_TAG = 20200923.3
 CBC_TAG = 2.10.5
 CGL_TAG = 0.60.3
diff --git a/makefiles/Makefile.third_party.win.mk b/makefiles/Makefile.third_party.win.mk
index 66f6705e27..b2b7fc8bdc 100644
--- a/makefiles/Makefile.third_party.win.mk
+++ b/makefiles/Makefile.third_party.win.mk
@@ -35,7 +35,7 @@ SWIG_BINARY = $(WINDOWS_SWIG_BINARY)
 # tags of dependencies to checkout.
 ZLIB_TAG = 1.2.11
 ZLIB_ARCHIVE_TAG = 1211
-PROTOBUF_TAG = v3.15.3
+PROTOBUF_TAG = v3.15.7
 ABSL_TAG = 20200923.3
 # We are using a CBC archive containing all coin-or project
 # since Clp 2.17.5+ is broken we need to stick with Cbc 2.10.4
diff --git a/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in b/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in
index 6c4f6b8ebf..bcb42535ec 100644
--- a/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in
+++ b/ortools/dotnet/Google.OrTools/Google.OrTools.csproj.in
@@ -141,7 +141,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.15.3"/>
+    <PackageReference Include="Google.Protobuf" Version="3.15.7"/>
   </ItemGroup>
 
   <!-- Need to add required runtime dependencies so Meta-Project will pull runtime Nuget(s) -->
diff --git a/ortools/java/pom-full.xml.in b/ortools/java/pom-full.xml.in
index cb73b0feb3..ce9ba2e6d0 100644
--- a/ortools/java/pom-full.xml.in
+++ b/ortools/java/pom-full.xml.in
@@ -95,7 +95,7 @@
   <dependency>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-java</artifactId>
-    <version>3.15.3</version>
+    <version>3.15.7</version>
   </dependency>
 </dependencies>
 
diff --git a/ortools/java/pom-local.xml.in b/ortools/java/pom-local.xml.in
index f2201f9e75..5b1a24d22d 100644
--- a/ortools/java/pom-local.xml.in
+++ b/ortools/java/pom-local.xml.in
@@ -81,7 +81,7 @@
   <dependency>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-java</artifactId>
-    <version>3.15.3</version>
+    <version>3.15.7</version>
   </dependency>
 </dependencies>
 
diff --git a/ortools/java/pom.xml.in b/ortools/java/pom.xml.in
index 69631d8b4f..3aeb6b4b74 100644
--- a/ortools/java/pom.xml.in
+++ b/ortools/java/pom.xml.in
@@ -69,7 +69,7 @@
   <dependency>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-java</artifactId>
-    <version>3.15.3</version>
+    <version>3.15.7</version>
   </dependency>
   <dependency>
     <groupId>junit</groupId>
diff --git a/ortools/python/setup.py.in b/ortools/python/setup.py.in
index f0022dc8d1..2fcf1611c7 100644
--- a/ortools/python/setup.py.in
+++ b/ortools/python/setup.py.in
@@ -42,7 +42,7 @@ setup(
     version='@PROJECT_VERSION@',
     packages=find_packages(),
     install_requires=[
-        'protobuf >= 3.15.3',
+        'protobuf >= 3.15.7',
         'absl-py >= 0.11',
     ],
     package_data={
diff --git a/patches/protobuf-v3.15.3.patch b/patches/protobuf-v3.15.7.patch
similarity index 72%
rename from patches/protobuf-v3.15.3.patch
rename to patches/protobuf-v3.15.7.patch
index afdb01c448..f53287d6f9 100644
--- a/patches/protobuf-v3.15.3.patch
+++ b/patches/protobuf-v3.15.7.patch
@@ -1,5 +1,5 @@
 diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
-index 52661f522..79aea8b4d 100644
+index 5c3b6e451..9834a16d4 100644
 --- a/cmake/CMakeLists.txt
 +++ b/cmake/CMakeLists.txt
 @@ -16,6 +16,16 @@ if(POLICY CMP0048)
@@ -24,10 +24,10 @@ index 52661f522..79aea8b4d 100644
  option(protobuf_BUILD_PROTOC_BINARIES "Build libprotoc and protoc compiler" ON)
  option(protobuf_BUILD_LIBPROTOC "Build libprotoc" OFF)
 +option(protobuf_BUILD_EXPORT "Build export to use build directory" ON)
+ option(protobuf_DISABLE_RTTI "Remove runtime type information in the binaries" OFF)
  if (BUILD_SHARED_LIBS)
    set(protobuf_BUILD_SHARED_LIBS_DEFAULT ON)
- else (BUILD_SHARED_LIBS)
-@@ -52,7 +63,7 @@ else (BUILD_SHARED_LIBS)
+@@ -53,7 +64,7 @@ else (BUILD_SHARED_LIBS)
  endif (BUILD_SHARED_LIBS)
  option(protobuf_BUILD_SHARED_LIBS "Build Shared Libraries" ${protobuf_BUILD_SHARED_LIBS_DEFAULT})
  include(CMakeDependentOption)
@@ -36,16 +36,7 @@ index 52661f522..79aea8b4d 100644
    "NOT protobuf_BUILD_SHARED_LIBS" OFF)
  set(protobuf_WITH_ZLIB_DEFAULT ON)
  option(protobuf_WITH_ZLIB "Build with zlib support" ${protobuf_WITH_ZLIB_DEFAULT})
-@@ -65,6 +76,8 @@ include(protobuf-options.cmake)
- # Overrides for option dependencies
- if (protobuf_BUILD_PROTOC_BINARIES OR protobuf_BUILD_TESTS)
-   set(protobuf_BUILD_LIBPROTOC ON)
-+else()
-+  set(protobuf_BUILD_LIBPROTOC OFF)
- endif ()
- # Path to main configure script
- set(protobuf_CONFIGURE_SCRIPT "../configure.ac")
-@@ -124,24 +137,12 @@ endif (CMAKE_USE_PTHREADS_INIT)
+@@ -129,24 +140,16 @@ endif (CMAKE_USE_PTHREADS_INIT)
  
  set(_protobuf_FIND_ZLIB)
  if (protobuf_WITH_ZLIB)
@@ -71,12 +62,16 @@ index 52661f522..79aea8b4d 100644
 +    find_package(ZLIB REQUIRED)
 +  endif()
 +  set(HAVE_ZLIB 1)
-+  set(_protobuf_FIND_ZLIB "if(NOT ZLIB_FOUND AND NOT TARGET ZLIB::ZLIB)\n
-+  find_package(ZLIB REQUIRED)\nendif()")
++  # FindZLIB module define ZLIB_INCLUDE_DIRS variable
++  # Set ZLIB_INCLUDE_DIRECTORIES for compatible
++  set(ZLIB_INCLUDE_DIRECTORIES ${ZLIB_INCLUDE_DIRECTORIES} ${ZLIB_INCLUDE_DIRS})
++  # Using imported target if exists
++  set(ZLIB_LIBRARIES ZLIB::ZLIB)
++  set(_protobuf_FIND_ZLIB "if(NOT ZLIB_FOUND AND NOT TARGET ZLIB::ZLIB)\n  find_package(ZLIB REQUIRED)\nendif()")
  endif (protobuf_WITH_ZLIB)
  
  if (HAVE_ZLIB)
-@@ -231,7 +232,6 @@ endif (MSVC)
+@@ -236,7 +239,6 @@ endif (MSVC)
  get_filename_component(protobuf_source_dir ${protobuf_SOURCE_DIR} PATH)
  
  include_directories(
@@ -85,14 +80,13 @@ index 52661f522..79aea8b4d 100644
    ${protobuf_source_dir}/src)
  
 diff --git a/cmake/install.cmake b/cmake/install.cmake
-index 4091bc8af..587d6d15a 100644
+index 9dd6e7710..e99c89940 100644
 --- a/cmake/install.cmake
 +++ b/cmake/install.cmake
-@@ -119,18 +119,19 @@ configure_file(protobuf-options.cmake
-   ${CMAKE_INSTALL_CMAKEDIR}/protobuf-options.cmake @ONLY)
+@@ -124,17 +124,19 @@ configure_file(protobuf-options.cmake
  
  # Allows the build directory to be used as a find directory.
--
+ 
 -if (protobuf_BUILD_PROTOC_BINARIES)
 -  export(TARGETS libprotobuf-lite libprotobuf libprotoc protoc
 -    NAMESPACE protobuf::
@@ -109,27 +103,14 @@ index 4091bc8af..587d6d15a 100644
 +    export(TARGETS libprotobuf-lite libprotobuf libprotoc protoc
 +      NAMESPACE protobuf::
 +      FILE ${CMAKE_INSTALL_CMAKEDIR}/protobuf-targets.cmake
-+      )
++    )
 +  else (protobuf_BUILD_PROTOC_BINARIES)
 +    export(TARGETS libprotobuf-lite libprotobuf
 +      NAMESPACE protobuf::
 +      FILE ${CMAKE_INSTALL_CMAKEDIR}/protobuf-targets.cmake
-+      )
++    )
 +  endif (protobuf_BUILD_PROTOC_BINARIES)
 +endif()
  
  install(EXPORT protobuf-targets
    DESTINATION "${CMAKE_INSTALL_CMAKEDIR}"
-diff --git a/cmake/libprotobuf.cmake b/cmake/libprotobuf.cmake
-index a5be494fb..9934e6e8a 100644
---- a/cmake/libprotobuf.cmake
-+++ b/cmake/libprotobuf.cmake
-@@ -116,7 +116,7 @@ add_library(libprotobuf ${protobuf_SHARED_OR_STATIC}
-   ${libprotobuf_lite_files} ${libprotobuf_files} ${libprotobuf_includes} ${libprotobuf_rc_files})
- target_link_libraries(libprotobuf ${CMAKE_THREAD_LIBS_INIT})
- if(protobuf_WITH_ZLIB)
--  target_link_libraries(libprotobuf ${ZLIB_LIBRARIES})
-+  target_link_libraries(libprotobuf ZLIB::ZLIB)
- endif()
- if(protobuf_LINK_LIBATOMIC)
-   target_link_libraries(libprotobuf atomic)
diff --git a/tools/setup.py.in b/tools/setup.py.in
index f985cfe607..1be0724676 100644
--- a/tools/setup.py.in
+++ b/tools/setup.py.in
@@ -42,7 +42,7 @@ setup(
     version='VVVV',
     packages=find_packages(),
     install_requires=[
-        'protobuf >= 3.15.3',
+        'protobuf >= 3.15.7',
         'absl-py >= 0.11',
     ],
     package_data={