diff --git a/NEWS b/NEWS
index 3e559dcfc..f183d874c 100644
--- a/NEWS
+++ b/NEWS
@@ -27,6 +27,10 @@ ver 0.24 (not yet released)
 * remove Haiku support
 * require libfmt 7 or later
 
+ver 0.23.12 (not yet released)
+* tags
+  - fix crash bug due to race condition
+
 ver 0.23.11 (2022/11/28)
 * database
   - simple: move default database to ~/.cache/mpd/db from ~/.cache/mpd.db
diff --git a/android/AndroidManifest.xml b/android/AndroidManifest.xml
index 41320212f..68028d594 100644
--- a/android/AndroidManifest.xml
+++ b/android/AndroidManifest.xml
@@ -2,8 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="org.musicpd"
           android:installLocation="auto"
-          android:versionCode="70"
-          android:versionName="0.23.11">
+          android:versionCode="71"
+          android:versionName="0.23.12">
 
   <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="30"/>
 
diff --git a/src/RemoteTagCache.hxx b/src/RemoteTagCache.hxx
index 116a753b5..4fa6fab6d 100644
--- a/src/RemoteTagCache.hxx
+++ b/src/RemoteTagCache.hxx
@@ -27,7 +27,11 @@
 #include "util/IntrusiveList.hxx"
 #include "util/IntrusiveHashSet.hxx"
 
+#include <array>
+#include <functional>
+#include <memory>
 #include <string>
+#include <utility>
 
 class RemoteTagCacheHandler;
 
diff --git a/src/io/FileReader.hxx b/src/io/FileReader.hxx
index fd3c709e9..c39b8f47e 100644
--- a/src/io/FileReader.hxx
+++ b/src/io/FileReader.hxx
@@ -42,6 +42,8 @@
 #include "io/UniqueFileDescriptor.hxx"
 #endif
 
+#include <cstdint>
+
 class Path;
 class FileInfo;
 
diff --git a/src/lib/curl/Easy.hxx b/src/lib/curl/Easy.hxx
index fd2cceef0..3bfcc0952 100644
--- a/src/lib/curl/Easy.hxx
+++ b/src/lib/curl/Easy.hxx
@@ -187,10 +187,6 @@ public:
 		SetOption(CURLOPT_POSTFIELDSIZE, (long)size);
 	}
 
-	void SetHttpPost(const struct curl_httppost *post) {
-		SetOption(CURLOPT_HTTPPOST, post);
-	}
-
 	template<typename T>
 	bool GetInfo(CURLINFO info, T value_r) const noexcept {
 		return ::curl_easy_getinfo(handle, info, value_r) == CURLE_OK;
@@ -200,10 +196,10 @@ public:
 	 * Returns the response body's size, or -1 if that is unknown.
 	 */
 	[[gnu::pure]]
-	int64_t GetContentLength() const noexcept {
-		double value;
-		return GetInfo(CURLINFO_CONTENT_LENGTH_DOWNLOAD, &value)
-			? (int64_t)value
+	curl_off_t GetContentLength() const noexcept {
+		curl_off_t value;
+		return GetInfo(CURLINFO_CONTENT_LENGTH_DOWNLOAD_T, &value)
+			? value
 			: -1;
 	}
 
diff --git a/src/tag/Builder.cxx b/src/tag/Builder.cxx
index 72dbd8eff..ee207308a 100644
--- a/src/tag/Builder.cxx
+++ b/src/tag/Builder.cxx
@@ -261,8 +261,14 @@ TagBuilder::RemoveAll() noexcept
 void
 TagBuilder::RemoveType(TagType type) noexcept
 {
+	if (items.empty())
+		/* don't acquire the tag_pool_lock if we're not going
+		   to call tag_pool_put_item() anyway */
+		return;
+
 	const auto begin = items.begin(), end = items.end();
 
+	const std::scoped_lock<Mutex> protect(tag_pool_lock);
 	items.erase(std::remove_if(begin, end,
 				   [type](TagItem *item) {
 					   if (item->type != type)