diff --git a/requirements.txt b/requirements.txt
index c23afd5..38d44f7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,13 +1,13 @@
 # Add here external Python modules dependencies, one per line. Module names
 # should match https://pypi.python.org/pypi names. For the full spec or
 # dependency lines, see https://pip.readthedocs.org/en/1.1/requirements.html
-sphinx
+sphinx < 4.4.0  # version 4.4.0 adds this kind of warning: "WARNING: hardcoded link 'https://archive.softwareheritage.org/api/1/vault/directory/doc/' could be replaced by an extlink (try using ':swh_web_api:`vault/directory/doc/`' instead)", which breaks the CI since we fail on warnings
 sphinxcontrib-httpdomain >= 1.8.0
 sphinxcontrib-images
 sphinxcontrib-programoutput
 sphinx-tabs
 sphinx-reredirects
 sphinx_rtd_theme
 sphinx-click
 myst-parser
 sphinx-celery