diff --git a/server/middlewares/validators/videos/video-comments.ts b/server/middlewares/validators/videos/video-comments.ts
index 665fb04c8..91ae31ec2 100644
--- a/server/middlewares/validators/videos/video-comments.ts
+++ b/server/middlewares/validators/videos/video-comments.ts
@@ -8,7 +8,14 @@ import { logger } from '../../../helpers/logger'
 import { AcceptResult, isLocalVideoCommentReplyAccepted, isLocalVideoThreadAccepted } from '../../../lib/moderation'
 import { Hooks } from '../../../lib/plugins/hooks'
 import { MCommentOwnerVideoReply, MVideo, MVideoFullLight } from '../../../types/models/video'
-import { areValidationErrors, doesVideoCommentExist, doesVideoCommentThreadExist, doesVideoExist, isValidVideoIdParam } from '../shared'
+import {
+  areValidationErrors,
+  checkCanSeeVideoIfPrivate,
+  doesVideoCommentExist,
+  doesVideoCommentThreadExist,
+  doesVideoExist,
+  isValidVideoIdParam
+} from '../shared'
 
 const listVideoCommentsValidator = [
   query('isLocal')
@@ -47,6 +54,13 @@ const listVideoCommentThreadsValidator = [
     if (areValidationErrors(req, res)) return
     if (!await doesVideoExist(req.params.videoId, res, 'only-video')) return
 
+    if (!await checkCanSeeVideoIfPrivate(req, res, res.locals.onlyVideo)) {
+      return res.fail({
+        status: HttpStatusCode.FORBIDDEN_403,
+        message: 'Cannot list comments of private/internal/blocklisted video'
+      })
+    }
+
     return next()
   }
 ]
@@ -64,6 +78,13 @@ const listVideoThreadCommentsValidator = [
     if (!await doesVideoExist(req.params.videoId, res, 'only-video')) return
     if (!await doesVideoCommentThreadExist(req.params.threadId, res.locals.onlyVideo, res)) return
 
+    if (!await checkCanSeeVideoIfPrivate(req, res, res.locals.onlyVideo)) {
+      return res.fail({
+        status: HttpStatusCode.FORBIDDEN_403,
+        message: 'Cannot list threads of private/internal/blocklisted video'
+      })
+    }
+
     return next()
   }
 ]
diff --git a/server/tests/api/check-params/video-comments.ts b/server/tests/api/check-params/video-comments.ts
index 63c3582e9..829f3c8b1 100644
--- a/server/tests/api/check-params/video-comments.ts
+++ b/server/tests/api/check-params/video-comments.ts
@@ -3,7 +3,7 @@
 import 'mocha'
 import * as chai from 'chai'
 import { checkBadCountPagination, checkBadSortPagination, checkBadStartPagination } from '@server/tests/shared'
-import { HttpStatusCode, VideoCreateResult } from '@shared/models'
+import { HttpStatusCode, VideoCreateResult, VideoPrivacy } from '@shared/models'
 import {
   cleanupTests,
   createSingleServer,
@@ -24,6 +24,8 @@ describe('Test video comments API validator', function () {
   let userAccessToken: string
   let userAccessToken2: string
   let commentId: number
+  let privateCommentId: number
+  let privateVideo: VideoCreateResult
 
   // ---------------------------------------------------------------
 
@@ -39,12 +41,21 @@ describe('Test video comments API validator', function () {
       pathThread = '/api/v1/videos/' + video.uuid + '/comment-threads'
     }
 
+    {
+      privateVideo = await server.videos.upload({ attributes: { privacy: VideoPrivacy.PRIVATE } })
+    }
+
     {
       const created = await server.comments.createThread({ videoId: video.uuid, text: 'coucou' })
       commentId = created.id
       pathComment = '/api/v1/videos/' + video.uuid + '/comments/' + commentId
     }
 
+    {
+      const created = await server.comments.createThread({ videoId: privateVideo.uuid, text: 'coucou' })
+      privateCommentId = created.id
+    }
+
     {
       const user = { username: 'user1', password: 'my super password' }
       await server.users.create({ username: user.username, password: user.password })
@@ -78,6 +89,32 @@ describe('Test video comments API validator', function () {
         expectedStatus: HttpStatusCode.NOT_FOUND_404
       })
     })
+
+    it('Should fail with a private video without token', async function () {
+      await makeGetRequest({
+        url: server.url,
+        path: '/api/v1/videos/' + privateVideo.shortUUID + '/comment-threads',
+        expectedStatus: HttpStatusCode.UNAUTHORIZED_401
+      })
+    })
+
+    it('Should fail with another user token', async function () {
+      await makeGetRequest({
+        url: server.url,
+        token: userAccessToken,
+        path: '/api/v1/videos/' + privateVideo.shortUUID + '/comment-threads',
+        expectedStatus: HttpStatusCode.FORBIDDEN_403
+      })
+    })
+
+    it('Should succeed with the correct params', async function () {
+      await makeGetRequest({
+        url: server.url,
+        token: server.accessToken,
+        path: '/api/v1/videos/' + privateVideo.shortUUID + '/comment-threads',
+        expectedStatus: HttpStatusCode.OK_200
+      })
+    })
   })
 
   describe('When listing comments of a thread', function () {
@@ -97,7 +134,31 @@ describe('Test video comments API validator', function () {
       })
     })
 
+    it('Should fail with a private video without token', async function () {
+      await makeGetRequest({
+        url: server.url,
+        path: '/api/v1/videos/' + privateVideo.shortUUID + '/comment-threads/' + privateCommentId,
+        expectedStatus: HttpStatusCode.UNAUTHORIZED_401
+      })
+    })
+
+    it('Should fail with another user token', async function () {
+      await makeGetRequest({
+        url: server.url,
+        token: userAccessToken,
+        path: '/api/v1/videos/' + privateVideo.shortUUID + '/comment-threads/' + privateCommentId,
+        expectedStatus: HttpStatusCode.FORBIDDEN_403
+      })
+    })
+
     it('Should success with the correct params', async function () {
+      await makeGetRequest({
+        url: server.url,
+        token: server.accessToken,
+        path: '/api/v1/videos/' + privateVideo.shortUUID + '/comment-threads/' + privateCommentId,
+        expectedStatus: HttpStatusCode.OK_200
+      })
+
       await makeGetRequest({
         url: server.url,
         path: '/api/v1/videos/' + video.shortUUID + '/comment-threads/' + commentId,