From 7c93007aa6d3aed0d449124ee47cd129bbf17117 Mon Sep 17 00:00:00 2001
From: Sadie Powell <sadie@witchery.services>
Date: Sat, 13 Apr 2024 12:17:29 +0100
Subject: [PATCH] Avoid duplicate entries in ReplaceCert.

---
 modules/nickserv/ns_cert.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/modules/nickserv/ns_cert.cpp b/modules/nickserv/ns_cert.cpp
index 1c9d0ae80..a6a0a3bfe 100644
--- a/modules/nickserv/ns_cert.cpp
+++ b/modules/nickserv/ns_cert.cpp
@@ -111,6 +111,14 @@ public:
 
 		FOREACH_MOD(OnNickEraseCert, (this->nc, oldentry));
 		certmap.erase(oldentry);
+
+		if (std::find(this->certs.begin(), this->certs.end(), newentry) != this->certs.end())
+		{
+			// The cert we're upgrading to already exists.
+			this->certs.erase(it);
+			return;
+		}
+
 		*it = newentry;
 		certmap[newentry] = nc;
 		FOREACH_MOD(OnNickAddCert, (this->nc, newentry));