diff --git a/cmake/legacy.cmake b/cmake/legacy.cmake
index a3515e31..f84030ea 100644
--- a/cmake/legacy.cmake
+++ b/cmake/legacy.cmake
@@ -239,7 +239,7 @@ ExternalProject_Add(zeromq
 )
 
 list(APPEND packages flatbuffers)
-set(flatbuffers_version "23.5.26")
+set(flatbuffers_version "24.3.25")
 ExternalProject_Add(flatbuffers
   GIT_REPOSITORY https://github.com/google/flatbuffers GIT_TAG v${flatbuffers_version}
   ${CMAKE_DEFAULT_ARGS} CMAKE_ARGS
diff --git a/legacy/README.md b/legacy/README.md
index d74ec595..f454f273 100644
--- a/legacy/README.md
+++ b/legacy/README.md
@@ -107,7 +107,7 @@ please contact us.
 | faircmakemodules | 1.0.0        | https://github.com/FairRootGroup/FairCMakeModules |
 | fairlogger       | 2.0.0        | https://github.com/FairRootGroup/FairLogger |
 | fairmq           | 1.8.4        | https://github.com/FairRootGroup/FairMQ |
-| flatbuffers      | 23.5.26      | https://github.com/google/flatbuffers |
+| flatbuffers      | 24.3.25      | https://github.com/google/flatbuffers |
 | fmt              | 11.0.0       | https://github.com/fmtlib/fmt |
 | geant3           | 4-2_fairsoft | https://github.com/FairRootGroup/geant3 |
 | geant4           | 11.2.2       | https://geant4.web.cern.ch |