diff --git a/poetry.lock b/poetry.lock
index 7e7a2e95760..5c2a58ef77d 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -16,17 +16,17 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [[package]]
 name = "attrs"
-version = "20.3.0"
+version = "21.1.0"
 description = "Classes Without Boilerplate"
 category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [package.extras]
-dev = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "zope.interface", "furo", "sphinx", "pre-commit"]
-docs = ["furo", "sphinx", "zope.interface"]
-tests = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "zope.interface"]
-tests_no_zope = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six"]
+dev = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins", "zope.interface", "furo", "sphinx", "sphinx-notfound-page", "pre-commit"]
+docs = ["furo", "sphinx", "zope.interface", "sphinx-notfound-page"]
+tests = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins", "zope.interface"]
+tests_no_zope = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins"]
 
 [[package]]
 name = "cachecontrol"
@@ -665,7 +665,7 @@ socks = ["PySocks (>=1.5.6,!=1.5.7,<2.0)"]
 
 [[package]]
 name = "virtualenv"
-version = "20.4.6"
+version = "20.4.4"
 description = "Virtual Python Environment builder"
 category = "main"
 optional = false
@@ -714,7 +714,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=1.2.3)", "pytest-flake8", "pyt
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.6"
-content-hash = "c2361801df0387c1a84cf3e18aa510b4ae4bab585a203471351382eb8125c4d5"
+content-hash = "9d02b786fa736951d56bd71ef48a3c496bcb91ff39dea598f022de3538fb8e60"
 
 [metadata.files]
 appdirs = [
@@ -726,8 +726,8 @@ atomicwrites = [
     {file = "atomicwrites-1.4.0.tar.gz", hash = "sha256:ae70396ad1a434f9c7046fd2dd196fc04b12f9e91ffb859164193be8b6168a7a"},
 ]
 attrs = [
-    {file = "attrs-20.3.0-py2.py3-none-any.whl", hash = "sha256:31b2eced602aa8423c2aea9c76a724617ed67cf9513173fd3a4f03e3a929c7e6"},
-    {file = "attrs-20.3.0.tar.gz", hash = "sha256:832aa3cde19744e49938b91fea06d69ecb9e649c93ba974535d08ad92164f700"},
+    {file = "attrs-21.1.0-py2.py3-none-any.whl", hash = "sha256:8ee1e5f5a1afc5b19bdfae4fdf0c35ed324074bdce3500c939842c8f818645d9"},
+    {file = "attrs-21.1.0.tar.gz", hash = "sha256:3901be1cb7c2a780f14668691474d9252c070a756be0a9ead98cfeabfa11aeb8"},
 ]
 cachecontrol = [
     {file = "CacheControl-0.12.6-py2.py3-none-any.whl", hash = "sha256:10d056fa27f8563a271b345207402a6dcce8efab7e5b377e270329c62471b10d"},
@@ -1087,8 +1087,8 @@ urllib3 = [
     {file = "urllib3-1.25.10.tar.gz", hash = "sha256:91056c15fa70756691db97756772bb1eb9678fa585d9184f24534b100dc60f4a"},
 ]
 virtualenv = [
-    {file = "virtualenv-20.4.6-py2.py3-none-any.whl", hash = "sha256:307a555cf21e1550885c82120eccaf5acedf42978fd362d32ba8410f9593f543"},
-    {file = "virtualenv-20.4.6.tar.gz", hash = "sha256:72cf267afc04bf9c86ec932329b7e94db6a0331ae9847576daaa7ca3c86b29a4"},
+    {file = "virtualenv-20.4.4-py2.py3-none-any.whl", hash = "sha256:a935126db63128861987a7d5d30e23e8ec045a73840eeccb467c148514e29535"},
+    {file = "virtualenv-20.4.4.tar.gz", hash = "sha256:09c61377ef072f43568207dc8e46ddeac6bcdcaf288d49011bda0e7f4d38c4a2"},
 ]
 wcwidth = [
     {file = "wcwidth-0.2.5-py2.py3-none-any.whl", hash = "sha256:beb4802a9cebb9144e99086eff703a642a13d6a0052920003a230f3294bbe784"},
diff --git a/pyproject.toml b/pyproject.toml
index 67e3af8b69d..1e61cc4598a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -44,7 +44,8 @@ shellingham = "^1.1"
 tomlkit = ">=0.7.0,<1.0.0"
 pexpect = "^4.7.0"
 packaging = "^20.4"
-virtualenv = "^20.4.3"
+# temporarily clamped due to https://github.com/pypa/pip/issues/9953
+virtualenv = ">=20.4.3,<20.4.5"
 keyring = ">=21.2.0"
 entrypoints = "^0.3"
 importlib-metadata = {version = "^1.6.0", python = "<3.8"}