diff --git a/macros.pyproject b/macros.pyproject
index 4306b9e..6709fe9 100644
--- a/macros.pyproject
+++ b/macros.pyproject
@@ -219,7 +219,7 @@ if [ -f %{__python3} ]; then
   echo -n > %{_pyproject_buildrequires}
   %{_pyproject_build_flags} \\\
   TMPDIR="%{_pyproject_builddir}" \\\
-  RPM_TOXENV="%{toxenv}" HOSTNAME="rpmbuild" %{__python3} -Bs %{_rpmconfigdir}/redhat/pyproject_buildrequires.py %{?!_python_no_extras_requires:--generate-extras} --python3_pkgversion %{python3_pkgversion} --wheeldir %{_pyproject_wheeldir} --output %{_pyproject_buildrequires} %{?**} >&2
+  RPM_TOXENV="%{toxenv}" FEDORA=%{?fedora} HOSTNAME="rpmbuild" %{__python3} -Bs %{_rpmconfigdir}/redhat/pyproject_buildrequires.py %{?!_python_no_extras_requires:--generate-extras} --python3_pkgversion %{python3_pkgversion} --wheeldir %{_pyproject_wheeldir} --output %{_pyproject_buildrequires} %{?**} >&2
   cat %{_pyproject_buildrequires}
 fi
 # Incomplete .dist-info dir might confuse importlib.metadata
diff --git a/pyproject-rpm-macros.spec b/pyproject-rpm-macros.spec
index 629df6c..843e282 100644
--- a/pyproject-rpm-macros.spec
+++ b/pyproject-rpm-macros.spec
@@ -193,6 +193,7 @@ export HOSTNAME="rpmbuild"  # to speedup tox in network-less mock, see rhbz#1856
 %changelog
 * Tue Mar 11 2025 Miro Hrončok <mhroncok@redhat.com> - 1.18.0-1
 - Make %%pyproject_buildrequires -t/-e and %%tox fail when no suitable tox configuration exists
+- The %%pyproject_buildrequires -t/-e case is temporarily allowed on Fedora 40-42
 - Requires tox-current-env >= 0.0.16
 
 * Thu Jan 30 2025 Miro Hrončok <miro@hroncok.cz> - 1.17.0-1
diff --git a/pyproject_buildrequires.py b/pyproject_buildrequires.py
index 2bda7cd..d90cf1e 100644
--- a/pyproject_buildrequires.py
+++ b/pyproject_buildrequires.py
@@ -22,6 +22,15 @@ from pyproject_wheel import parse_config_settings_args
 # Allow only the forms we know we can handle.
 VERSION_RE = re.compile(r'[a-zA-Z0-9.-]+(\.\*)?')
 
+# To avoid breakage on Fedora 40-42,
+# we don't assert tox configuration there.
+# This can be removed when Fedora 42 goes EOL.
+# Note that %tox still uses --assert-config
+# because %tox without config is dangerous (false sense of tests).
+# Running %pyproject_buildrequires -t/-e without tox config is wrong, but not dangerous.
+FEDORA = int(os.getenv('FEDORA') or 0)
+TOX_ASSERT_CONFIG_OPTS = ('--assert-config',) if 40 <= FEDORA < 43 else ()
+
 
 class EndPass(Exception):
     """End current pass of generating requirements"""
@@ -426,7 +435,7 @@ def generate_tox_requirements(toxenv, requirements):
              '--print-deps-to', deps.name,
              '--print-extras-to', extras.name,
              '--no-provision', provision.name,
-             '--assert-config',
+             *TOX_ASSERT_CONFIG_OPTS,
              '-q', '-r', '-e', toxenv],
             check=False,
             encoding='utf-8',