diff --git a/CHANGELOG.md b/CHANGELOG.md
index 42311c3c..b54ed985 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,17 @@
 # Changelog
 All notable changes to Oragono will be documented in this file.
 
+## [2.5.1] - 2021-02-02
+
+Oragono 2.5.1 is a bugfix release that fixes a significant security issue. We apologize for the oversight.
+
+This release includes no changes to the config file format or the database.
+
+Many thanks to [@xnaas](https://github.com/xnaas) for reporting the issue.
+
+### Security
+* Fix an incorrect permissions check in NickServ (#1520, thanks [@xnaas](https://github.com/xnaas)!)
+
 ## [2.5.0] - 2021-01-31
 
 We're pleased to announce Oragono 2.5.0, a new stable release.
diff --git a/irc/version.go b/irc/version.go
index 0053dde9..aa61e6eb 100644
--- a/irc/version.go
+++ b/irc/version.go
@@ -7,7 +7,7 @@ import "fmt"
 
 const (
 	// SemVer is the semantic version of Oragono.
-	SemVer = "2.6.0-unreleased"
+	SemVer = "2.5.1"
 )
 
 var (