diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 19ad11d9..23a84cce 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -33,6 +33,7 @@ jobs:
             api.github.com:443
             release-assets.githubusercontent.com:443
             uploads.github.com:443
+            timestamp.githubapp.com:443
             pypi.org:443
             files.pythonhosted.org:443
             packages.microsoft.com:443
@@ -341,6 +342,8 @@ jobs:
           github.com:443
           api.github.com:443
           release-assets.githubusercontent.com:443
+          uploads.github.com:443
+          timestamp.githubapp.com:443
           pypi.org:443
           files.pythonhosted.org:443
           fulcio.sigstore.dev:443
diff --git a/.github/workflows/source-provenance.yml b/.github/workflows/source-provenance.yml
index f51c1d29..09ebab93 100644
--- a/.github/workflows/source-provenance.yml
+++ b/.github/workflows/source-provenance.yml
@@ -27,7 +27,9 @@ jobs:
           allowed-endpoints: >+
             github.com:443
             api.github.com:443
+            release-assets.githubusercontent.com:443
             uploads.github.com:443
+            timestamp.githubapp.com:443
             fulcio.sigstore.dev:443
             rekor.sigstore.dev:443
             tuf-repo-cdn.sigstore.dev:443
@@ -60,6 +62,7 @@ jobs:
             github.com:443
             api.github.com:443
             uploads.github.com:443
+            timestamp.githubapp.com:443
             fulcio.sigstore.dev:443
             rekor.sigstore.dev:443
             tuf-repo-cdn.sigstore.dev:443
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a598ccf7..dd8b237e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -54,6 +54,7 @@ jobs:
             svn.code.sf.net:443
             api.github.com:443
             uploads.github.com:443
+            timestamp.githubapp.com:443
             fulcio.sigstore.dev:443
             rekor.sigstore.dev:443
             tuf-repo-cdn.sigstore.dev:443