diff --git a/cmake/legacy.cmake b/cmake/legacy.cmake
index de68e478..c436530f 100644
--- a/cmake/legacy.cmake
+++ b/cmake/legacy.cmake
@@ -412,7 +412,7 @@ ExternalProject_Add(vmc
 )
 
 list(APPEND packages geant3)
-set(geant3_version "4-2_fairsoft")
+set(geant3_version "4-3_fairsoft")
 ExternalProject_Add(geant3
   GIT_REPOSITORY https://github.com/FairRootGroup/geant3 GIT_TAG v${geant3_version}
   ${CMAKE_DEFAULT_ARGS} CMAKE_ARGS
diff --git a/legacy/README.md b/legacy/README.md
index b49b80ea..fa8562cc 100644
--- a/legacy/README.md
+++ b/legacy/README.md
@@ -109,7 +109,7 @@ please contact us.
 | fairmq           | 1.8.4        | https://github.com/FairRootGroup/FairMQ |
 | 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 |
+| geant3           | 4-3_fairsoft | https://github.com/FairRootGroup/geant3 |
 | geant4           | 11.2.2       | https://geant4.web.cern.ch |
 | geant4_vmc       | 6-6-p1       | https://github.com/vmc-project/geant4_vmc |
 | hepmc            | 2.06.11      | http://hepmc.web.cern.ch |