diff --git a/internal/handlers/egress_allowlist_defaults.yaml b/internal/handlers/egress_allowlist_defaults.yaml
index e80fddf..918176c 100644
--- a/internal/handlers/egress_allowlist_defaults.yaml
+++ b/internal/handlers/egress_allowlist_defaults.yaml
@@ -466,6 +466,11 @@ ecosystem_default_domains:
     # Official Microsoft .NET SDK/runtime build hosts.
     - builds.dotnet.microsoft.com
     - ci.dot.net
+    # .NET release metadata index (releases-index.json), served from Microsoft's
+    # production Azure Blob storage (documented in dotnet/core). Exact host: the
+    # "dotnetcli" account is globally unique and Microsoft-owned, so it cannot be
+    # spoofed.
+    - dotnetcli.blob.core.windows.net
   hex:
     - repo.hex.pm
     - hex.pm
diff --git a/internal/handlers/egress_allowlist_test.go b/internal/handlers/egress_allowlist_test.go
index 7af8f6f..0dba991 100644
--- a/internal/handlers/egress_allowlist_test.go
+++ b/internal/handlers/egress_allowlist_test.go
@@ -718,6 +718,7 @@ func TestEgressAllowlist_NewEntriesDoNotWidenBeyondExactHosts(t *testing.T) {
 		"https://evil.julialang-s3.julialang.org/bin",
 		"https://evil.maven.artifacts.atlassian.com/maven",
 		"https://evil.mirrors.huaweicloud.com/repository/npm",
+		"https://evil.dotnetcli.blob.core.windows.net/payload",
 	}
 
 	// Sibling hosts: names sharing a parent with an added entry. These pin the
@@ -901,6 +902,7 @@ func TestEgressAllowlist_AddedMissingDomainsAllowed(t *testing.T) {
 		"https://repo.broadcom.com/artifactory/repo",
 		"https://builds.dotnet.microsoft.com/dotnet/Sdk/x.zip",
 		"https://ci.dot.net/public/dotnet/x.nupkg",
+		"https://dotnetcli.blob.core.windows.net/dotnet/release-metadata/releases-index.json",
 		"https://charts.bitnami.com/bitnami/index.yaml",
 		"https://charts.jetstack.io/charts/cert-manager.tgz",
 		"https://prometheus-community.github.io/helm-charts/index.yaml",