diff --git a/auto_inject.lock b/auto_inject.lock
new file mode 100644
index 00000000000..b06f285d822
--- /dev/null
+++ b/auto_inject.lock
@@ -0,0 +1 @@
+0.57.1-1
diff --git a/tests/test_the_test/test_installer_versions.py b/tests/test_the_test/test_installer_versions.py
new file mode 100644
index 00000000000..49675cd9248
--- /dev/null
+++ b/tests/test_the_test/test_installer_versions.py
@@ -0,0 +1,39 @@
+import os
+from pathlib import Path
+
+import pytest
+
+from utils import installer_versions
+from utils import scenarios
+
+
+@scenarios.test_the_test
+class Test_InstallerVersions:
+    def test_custom_library_pins_injector_from_lock(self, monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+        lock = tmp_path / "auto_inject.lock"
+        lock.write_text("pinned-version\n", encoding="utf-8")
+        monkeypatch.setattr(installer_versions, "AUTO_INJECT_LOCK", lock)
+        monkeypatch.setenv("DD_INSTALLER_LIBRARY_VERSION", "custom-library")
+        monkeypatch.setenv("DD_INSTALLER_INJECTOR_VERSION", "custom-injector")
+
+        installer_versions.set_injector_version_from_lock()
+
+        assert os.environ["DD_INSTALLER_INJECTOR_VERSION"] == "pinned-version"
+
+    def test_default_library_does_not_set_injector(self, monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+        lock = tmp_path / "auto_inject.lock"
+        lock.write_text("pinned-version\n", encoding="utf-8")
+        monkeypatch.setattr(installer_versions, "AUTO_INJECT_LOCK", lock)
+        monkeypatch.delenv("DD_INSTALLER_LIBRARY_VERSION", raising=False)
+        monkeypatch.delenv("DD_INSTALLER_INJECTOR_VERSION", raising=False)
+
+        installer_versions.set_injector_version_from_lock()
+
+        assert "DD_INSTALLER_INJECTOR_VERSION" not in os.environ
+
+    def test_auto_inject_lock_format(self) -> None:
+        contents = installer_versions.AUTO_INJECT_LOCK.read_text(encoding="utf-8")
+
+        assert contents.endswith("\n")
+        assert contents.count("\n") == 1
+        assert contents.strip() == contents[:-1]
diff --git a/utils/_context/_scenarios/docker_ssi.py b/utils/_context/_scenarios/docker_ssi.py
index fdbd539ec27..0b17185a16b 100644
--- a/utils/_context/_scenarios/docker_ssi.py
+++ b/utils/_context/_scenarios/docker_ssi.py
@@ -18,6 +18,7 @@
 )
 from utils._context.docker import get_docker_client
 from utils.docker_ssi.docker_ssi_matrix_utils import resolve_runtime_version
+from utils.installer_versions import set_injector_version_from_lock
 from utils._logger import logger
 from utils.virtual_machine.vm_logger import vm_logger
 
@@ -72,7 +73,12 @@ def configure(self, config: pytest.Config):
         self._env = "prod" if config.option.ssi_env is None or config.option.ssi_env == "prod" else "dev"
         self.configuration["env"] = self._env
         self._custom_library_version = config.option.ssi_library_version
-        self._custom_injector_version = config.option.ssi_injector_version
+        set_injector_version_from_lock()
+        self._custom_injector_version = (
+            os.getenv("DD_INSTALLER_INJECTOR_VERSION")
+            if os.getenv("DD_INSTALLER_LIBRARY_VERSION")
+            else config.option.ssi_injector_version
+        )
 
         # The runtime that we want to install on the base image. it could be empty if we don't need to install a runtime
         self._installable_runtime = (
diff --git a/utils/installer_versions.py b/utils/installer_versions.py
new file mode 100644
index 00000000000..854982771ba
--- /dev/null
+++ b/utils/installer_versions.py
@@ -0,0 +1,11 @@
+import os
+from pathlib import Path
+
+
+AUTO_INJECT_LOCK = Path(__file__).resolve().parents[1] / "auto_inject.lock"
+
+
+def set_injector_version_from_lock() -> None:
+    """Pin the injector when testing a custom library package."""
+    if os.getenv("DD_INSTALLER_LIBRARY_VERSION"):
+        os.environ["DD_INSTALLER_INJECTOR_VERSION"] = AUTO_INJECT_LOCK.read_text(encoding="utf-8").strip()
diff --git a/utils/scripts/ci_orchestrators/external_gitlab_pipeline.py b/utils/scripts/ci_orchestrators/external_gitlab_pipeline.py
index 7bfc4c11af3..29fa061990b 100644
--- a/utils/scripts/ci_orchestrators/external_gitlab_pipeline.py
+++ b/utils/scripts/ci_orchestrators/external_gitlab_pipeline.py
@@ -2,6 +2,7 @@
 import os
 
 from utils.const import COMPONENT_GROUPS
+from utils.installer_versions import set_injector_version_from_lock
 
 # List of allowed variables
 ALLOWED_VARIABLES = [
@@ -56,6 +57,8 @@ def main(language: str | None = None) -> None:
         language (str): The language to filter the pipeline for.
         if it's None or not a language, the pipeline will be generated for all languages
     """
+    set_injector_version_from_lock()
+
     # Filter environment variables
     new_variables = {var: os.getenv(var) for var in ALLOWED_VARIABLES if os.getenv(var) is not None}
 
diff --git a/utils/scripts/ci_orchestrators/gitlab_exporter.py b/utils/scripts/ci_orchestrators/gitlab_exporter.py
index de0810b8621..630084137c0 100644
--- a/utils/scripts/ci_orchestrators/gitlab_exporter.py
+++ b/utils/scripts/ci_orchestrators/gitlab_exporter.py
@@ -4,6 +4,7 @@
 import json
 from utils._context._scenarios import get_all_scenarios
 from utils._context._scenarios.core import Scenario
+from utils.installer_versions import set_injector_version_from_lock
 from utils.k8s.k8s_components_parser import K8sComponentsParser
 
 
@@ -68,6 +69,7 @@ def print_gitlab_pipeline(language: str, matrix_data: dict[str, dict], ci_enviro
 
 
 def print_ssi_gitlab_pipeline(language: str, matrix_data: dict[str, dict], ci_environment: str) -> None:
+    set_injector_version_from_lock()
     result_pipeline = {}  # type: dict
     result_pipeline["workflow"] = {"name": f"{language} SSI"}
     result_pipeline["include"] = []
diff --git a/utils/virtual_machine/virtual_machines.py b/utils/virtual_machine/virtual_machines.py
index 99e89ab769c..8d3d87bcf24 100644
--- a/utils/virtual_machine/virtual_machines.py
+++ b/utils/virtual_machine/virtual_machines.py
@@ -5,6 +5,7 @@
 
 import paramiko
 
+from utils.installer_versions import set_injector_version_from_lock
 from utils.virtual_machine.virtual_machine_provisioner import Provision, _DeployedWeblog
 
 # The AWS AMI name is limited to 128 characters (119 usable + 9 added by AWS).
@@ -21,6 +22,7 @@ def __init__(self) -> None:
 
 class DataDogConfig:
     def __init__(self) -> None:
+        set_injector_version_from_lock()
         self.dd_api_key = os.getenv("DD_API_KEY_ONBOARDING")
         self.dd_app_key = os.getenv("DD_APP_KEY_ONBOARDING")
         self.docker_login = os.getenv("DOCKER_LOGIN")