diff --git a/package-source-builder/overlay/usr/bin/apertis-pkg-pull-updates b/package-source-builder/overlay/usr/bin/apertis-pkg-pull-updates
index 4c4713920670e512118d90334e81d7391157da03..d69809d1d66a6a41e151bf21b646a9336b74bcb9 100755
--- a/package-source-builder/overlay/usr/bin/apertis-pkg-pull-updates
+++ b/package-source-builder/overlay/usr/bin/apertis-pkg-pull-updates
@@ -220,6 +220,16 @@ def import_sources(local_dsc, upstream_suite):
       ],
       env={'GBP_CONF_FILES': '/dev/null' }, # prevent the debian/gbp.conf in packages from interfering
       check=True)
+  # gbp puts all the new changelog entries in the commit message, generating
+  # big walls of text when, for instance, importing the version from bullseye
+  # on top of the buster one
+  # GitLab then puts the whole log message in the CI_COMMIT_MESSAGE env var,
+  # which is passed on the docker command line, resulting in a error:
+  #   standard_init_linux.go:219: exec user process caused: argument list too long
+  # https://gitlab.com/gitlab-org/gitlab-runner/-/issues/26624#note_529234097
+  # to avoid that, trim the message to only keep the first line
+  shortmessage = git("log", "--format=%s", "-n1")
+  git("commit", "--amend", f"--message={shortmessage}")
 
 def main():
   parser = argparse.ArgumentParser(description='Pull updates from the upstream repositories')