diff --git a/locales/index.d.ts b/locales/index.d.ts
index 39feda5075..5b7df00f93 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -10218,6 +10218,10 @@ export interface Locale extends ILocale {
          * Declined
          */
         "decline": string;
+        /**
+         * Set content warning for user
+         */
+        "setMandatoryCW": string;
         /**
          * Set remote instance as NSFW
          */
diff --git a/packages/backend/src/server/api/endpoints/admin/cw-user.ts b/packages/backend/src/server/api/endpoints/admin/cw-user.ts
index d48ca565a4..bdcfa6a0d9 100644
--- a/packages/backend/src/server/api/endpoints/admin/cw-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/cw-user.ts
@@ -9,6 +9,7 @@ import type { UsersRepository } from '@/models/_.js';
 import { DI } from '@/di-symbols.js';
 import { CacheService } from '@/core/CacheService.js';
 import { GlobalEventService } from '@/core/GlobalEventService.js';
+import { ModerationLogService } from '@/core/ModerationLogService.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -34,18 +35,31 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private readonly usersRepository: UsersRepository,
 
 		private readonly globalEventService: GlobalEventService,
+		private readonly cacheService: CacheService,
+		private readonly moderationLogService: ModerationLogService,
 	) {
-		super(meta, paramDef, async ps => {
-			const result = await this.usersRepository.update(ps.userId, {
+		super(meta, paramDef, async (ps, me) => {
+			const user = await this.cacheService.findUserById(ps.userId);
+
+			// Skip if there's nothing to do
+			if (user.mandatoryCW === ps.cw) return;
+
+			// Log event first.
+			// This ensures that we don't "lose" the log if an error occurs
+			await this.moderationLogService.log(me, 'setMandatoryCW', {
+				newCW: ps.cw,
+				oldCW: user.mandatoryCW,
+				userId: user.id,
+				userUsername: user.username,
+				userHost: user.host,
+			});
+
+			await this.usersRepository.update(ps.userId, {
 				// Collapse empty strings to null
 				// eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
 				mandatoryCW: ps.cw || null,
 			});
 
-			if (result.affected && result.affected < 1) {
-				throw new Error('No such user');
-			}
-
 			// Synchronize caches and other processes
 			this.globalEventService.publishInternalEvent('localUserUpdated', { id: ps.userId });
 		});
diff --git a/packages/backend/src/types.ts b/packages/backend/src/types.ts
index 067481d9da..b359fa5a39 100644
--- a/packages/backend/src/types.ts
+++ b/packages/backend/src/types.ts
@@ -100,6 +100,7 @@ export const moderationLogTypes = [
 	'deleteGlobalAnnouncement',
 	'deleteUserAnnouncement',
 	'resetPassword',
+	'setMandatoryCW',
 	'setRemoteInstanceNSFW',
 	'unsetRemoteInstanceNSFW',
 	'suspendRemoteInstance',
@@ -261,6 +262,13 @@ export type ModerationLogPayloads = {
 		userUsername: string;
 		userHost: string | null;
 	};
+	setMandatoryCW: {
+		newCW: string | null;
+		oldCW: string | null;
+		userId: string;
+		userUsername: string;
+		userHost: string | null;
+	};
 	setRemoteInstanceNSFW: {
 		id: string;
 		host: string;
diff --git a/packages/frontend/src/pages/admin/modlog.ModLog.vue b/packages/frontend/src/pages/admin/modlog.ModLog.vue
index 2e5c820054..741de875bc 100644
--- a/packages/frontend/src/pages/admin/modlog.ModLog.vue
+++ b/packages/frontend/src/pages/admin/modlog.ModLog.vue
@@ -22,6 +22,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 				[$style.logYellow]: [
 					'markSensitiveDriveFile',
 					'resetPassword',
+					'setMandatoryCW',
 					'suspendRemoteInstance',
 					'setRemoteInstanceNSFW',
 					'unsetRemoteInstanceNSFW',
@@ -55,6 +56,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 		<span v-else-if="log.type === 'decline'">: @{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }}</span>
 		<span v-else-if="log.type === 'unsuspend'">: @{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }}</span>
 		<span v-else-if="log.type === 'resetPassword'">: @{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }}</span>
+		<span v-else-if="log.type === 'setMandatoryCW'">: @{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }}</span>
 		<span v-else-if="log.type === 'assignRole'">: @{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }} <i class="ti ti-arrow-right"></i> {{ log.info.roleName }}</span>
 		<span v-else-if="log.type === 'unassignRole'">: @{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }} <i class="ti ti-equal-not"></i> {{ log.info.roleName }}</span>
 		<span v-else-if="log.type === 'createRole'">: {{ log.info.role.name }}</span>
@@ -123,6 +125,12 @@ SPDX-License-Identifier: AGPL-3.0-only
 		<template v-else-if="log.type === 'approve'">
 			<div>{{ i18n.ts.user }}: <MkA :to="`/admin/user/${log.info.userId}`" class="_link">@{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }}</MkA></div>
 		</template>
+		<template v-else-if="log.type === 'setMandatoryCW'">
+			<div>{{ i18n.ts.user }}: <MkA :to="`/admin/user/${log.info.userId}`" class="_link">@{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }}</MkA></div>
+			<div :class="$style.diff">
+				<CodeDiff :context="0" :hideHeader="true" :oldString="log.info.oldCW ?? ''" :newString="log.info.newCW ?? ''" maxHeight="150px"/>
+			</div>
+		</template>
 		<template v-else-if="log.type === 'unsuspend'">
 			<div>{{ i18n.ts.user }}: <MkA :to="`/admin/user/${log.info.userId}`" class="_link">@{{ log.info.userUsername }}{{ log.info.userHost ? '@' + log.info.userHost : '' }}</MkA></div>
 		</template>
diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index ee8bfe322c..25921d14c8 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -2609,6 +2609,9 @@ type ModerationLog = {
 } | {
     type: 'deleteUserAnnouncement';
     info: ModerationLogPayloads['deleteUserAnnouncement'];
+} | {
+    type: 'setMandatoryCW';
+    info: ModerationLogPayloads['setMandatoryCW'];
 } | {
     type: 'setRemoteInstanceNSFW';
     info: ModerationLogPayloads['setRemoteInstanceNSFW'];
@@ -2708,7 +2711,7 @@ type ModerationLog = {
 });
 
 // @public (undocumented)
-export const moderationLogTypes: readonly ["updateServerSettings", "suspend", "approve", "decline", "unsuspend", "updateUserNote", "addCustomEmoji", "updateCustomEmoji", "deleteCustomEmoji", "assignRole", "unassignRole", "createRole", "updateRole", "deleteRole", "clearQueue", "promoteQueue", "deleteDriveFile", "deleteNote", "createGlobalAnnouncement", "createUserAnnouncement", "updateGlobalAnnouncement", "updateUserAnnouncement", "deleteGlobalAnnouncement", "deleteUserAnnouncement", "resetPassword", "setRemoteInstanceNSFW", "unsetRemoteInstanceNSFW", "suspendRemoteInstance", "unsuspendRemoteInstance", "rejectRemoteInstanceReports", "acceptRemoteInstanceReports", "updateRemoteInstanceNote", "markSensitiveDriveFile", "unmarkSensitiveDriveFile", "resolveAbuseReport", "forwardAbuseReport", "updateAbuseReportNote", "createInvitation", "createAd", "updateAd", "deleteAd", "createAvatarDecoration", "updateAvatarDecoration", "deleteAvatarDecoration", "unsetUserAvatar", "unsetUserBanner", "createSystemWebhook", "updateSystemWebhook", "deleteSystemWebhook", "createAbuseReportNotificationRecipient", "updateAbuseReportNotificationRecipient", "deleteAbuseReportNotificationRecipient", "deleteAccount", "deletePage", "deleteFlash", "deleteGalleryPost"];
+export const moderationLogTypes: readonly ["updateServerSettings", "suspend", "approve", "decline", "unsuspend", "updateUserNote", "addCustomEmoji", "updateCustomEmoji", "deleteCustomEmoji", "assignRole", "unassignRole", "createRole", "updateRole", "deleteRole", "clearQueue", "promoteQueue", "deleteDriveFile", "deleteNote", "createGlobalAnnouncement", "createUserAnnouncement", "updateGlobalAnnouncement", "updateUserAnnouncement", "deleteGlobalAnnouncement", "deleteUserAnnouncement", "resetPassword", "setMandatoryCW", "setRemoteInstanceNSFW", "unsetRemoteInstanceNSFW", "suspendRemoteInstance", "unsuspendRemoteInstance", "rejectRemoteInstanceReports", "acceptRemoteInstanceReports", "updateRemoteInstanceNote", "markSensitiveDriveFile", "unmarkSensitiveDriveFile", "resolveAbuseReport", "forwardAbuseReport", "updateAbuseReportNote", "createInvitation", "createAd", "updateAd", "deleteAd", "createAvatarDecoration", "updateAvatarDecoration", "deleteAvatarDecoration", "unsetUserAvatar", "unsetUserBanner", "createSystemWebhook", "updateSystemWebhook", "deleteSystemWebhook", "createAbuseReportNotificationRecipient", "updateAbuseReportNotificationRecipient", "deleteAbuseReportNotificationRecipient", "deleteAccount", "deletePage", "deleteFlash", "deleteGalleryPost"];
 
 // @public (undocumented)
 type MuteCreateRequest = operations['mute___create']['requestBody']['content']['application/json'];
diff --git a/packages/misskey-js/src/consts.ts b/packages/misskey-js/src/consts.ts
index fcb19be303..96da0a8fad 100644
--- a/packages/misskey-js/src/consts.ts
+++ b/packages/misskey-js/src/consts.ts
@@ -147,6 +147,7 @@ export const moderationLogTypes = [
 	'deleteGlobalAnnouncement',
 	'deleteUserAnnouncement',
 	'resetPassword',
+	'setMandatoryCW',
 	'setRemoteInstanceNSFW',
 	'unsetRemoteInstanceNSFW',
 	'suspendRemoteInstance',
@@ -335,6 +336,13 @@ export type ModerationLogPayloads = {
 		userUsername: string;
 		userHost: string | null;
 	};
+	setMandatoryCW: {
+		newCW: string | null;
+		oldCW: string | null;
+		userId: string;
+		userUsername: string;
+		userHost: string | null;
+	};
 	setRemoteInstanceNSFW: {
 		id: string;
 		host: string;
diff --git a/packages/misskey-js/src/entities.ts b/packages/misskey-js/src/entities.ts
index b92c2537a1..3e88eae275 100644
--- a/packages/misskey-js/src/entities.ts
+++ b/packages/misskey-js/src/entities.ts
@@ -118,8 +118,8 @@ export type ModerationLog = {
 	type: 'deleteUserAnnouncement';
 	info: ModerationLogPayloads['deleteUserAnnouncement'];
 } | {
-	type: 'resetPassword';
-	info: ModerationLogPayloads['resetPassword'];
+	type: 'setMandatoryCW';
+	info: ModerationLogPayloads['setMandatoryCW'];
 } | {
 	type: 'setRemoteInstanceNSFW';
 	info: ModerationLogPayloads['setRemoteInstanceNSFW'];
diff --git a/sharkey-locales/en-US.yml b/sharkey-locales/en-US.yml
index a12d84e2f5..84dd527694 100644
--- a/sharkey-locales/en-US.yml
+++ b/sharkey-locales/en-US.yml
@@ -304,6 +304,7 @@ _abuseReport:
 _moderationLogTypes:
   approve: "Approved"
   decline: "Declined"
+  setMandatoryCW: "Set content warning for user"
   setRemoteInstanceNSFW: "Set remote instance as NSFW"
   unsetRemoteInstanceNSFW: "Set remote instance as NSFW"
   rejectRemoteInstanceReports: "Rejected reports from remote instance"