From dc87ac165f9e78599dec0e764b81637fd60cf232 Mon Sep 17 00:00:00 2001
From: Ben Lambert <ben@blam.sh>
Date: Sun, 22 Mar 2026 12:14:55 +0100
Subject: [PATCH] add changeset for loopback redirect URI fix (#33509)

---
 .changeset/loopback-redirect-uri-port.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/loopback-redirect-uri-port.md

diff --git a/.changeset/loopback-redirect-uri-port.md b/.changeset/loopback-redirect-uri-port.md
new file mode 100644
index 0000000000..e2f4d1b725
--- /dev/null
+++ b/.changeset/loopback-redirect-uri-port.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-auth-backend': patch
+---
+
+Fixed CIMD redirect URI matching to allow any port for localhost addresses per RFC 8252 Section 7.3. Native CLI clients use ephemeral ports for OAuth callbacks, which are now accepted when the registered redirect URI uses a localhost address.