diff --git a/profiles/package.mask b/profiles/package.mask
index 39befcd8c2c3c..5468b110b4c87 100644
--- a/profiles/package.mask
+++ b/profiles/package.mask
@@ -36,6 +36,21 @@
 
 #--- END OF EXAMPLES ---
 
+# Michał Górny <mgorny@gentoo.org> (2025-12-03)
+# Upstream changed how multiprocessing shares data between processes,
+# which means the upgrade randomly breaks some currently running Python
+# applications, notably Portage.
+~app-doc/python-docs-3.13.10
+~app-doc/python-docs-3.14.1
+~dev-lang/python-3.13.10
+~dev-lang/python-0.3.13.10
+~dev-lang/python-3.14.1
+~dev-lang/python-0.3.14.1
+~dev-python/python-tests-3.13.10
+~dev-python/python-tests-0.3.13.10
+~dev-python/python-tests-3.14.1
+~dev-python/python-tests-0.3.14.1
+
 # Jaco Kroon <jkroon@gentoo.org> (2025-12-02)
 # Dead upstream, limited usefulness.  If you're still using it please reach out
 # so we can discuss options.  Likely not worth the effort to fix the compiler