diff --git a/addons/mail/static/src/attachments/attachment_model.js b/addons/mail/static/src/attachments/attachment_model.js
index 52cf58d0504..74b7dfce150 100644
--- a/addons/mail/static/src/attachments/attachment_model.js
+++ b/addons/mail/static/src/attachments/attachment_model.js
@@ -119,12 +119,7 @@ export class Attachment {
         if (this.uploading && this.tmpUrl) {
             return this.tmpUrl;
         }
-        if (!this.accessToken && this.originThread?.model === "discuss.channel") {
-            return this.isImage
-                ? `/discuss/channel/${this.originThread.id}/image/${this.id}`
-                : `/discuss/channel/${this.originThread.id}/attachment/${this.id}`;
-        }
-        return this.isImage ? `/web/image/${this.id}` : `/web/content/ir.attachment/${this.id}`;
+        return this.isImage ? `/web/image/${this.id}` : `/web/content/${this.id}`;
     }
 
     /**
diff --git a/addons/mail/static/src/attachments/attachment_view.xml b/addons/mail/static/src/attachments/attachment_view.xml
index c325409a070..b3a3b7d210d 100644
--- a/addons/mail/static/src/attachments/attachment_view.xml
+++ b/addons/mail/static/src/attachments/attachment_view.xml
@@ -6,9 +6,9 @@
             <t t-if="state.thread.mainAttachment">
                 <h3 t-if="!state.thread.mainAttachment.isPdf" class="mt0 mb8 ps-2 text-muted float-end"><t t-esc="state.thread.mainAttachment.filename"/></h3>
                 <div t-if="state.thread.mainAttachment.isImage" class="o-mail-Attachment-imgContainer">
-                    <img id="attachment_img" class="img img-fluid d-block" t-attf-src="state.thread.mainAttachment.defaultSource"/>
+                    <img id="attachment_img" class="img img-fluid d-block" t-att-src="state.thread.mainAttachment.defaultSource"/>
                 </div>
-                <iframe t-if="state.thread.mainAttachment.isPdf" class="mb48" t-attf-src="state.thread.mainAttachment.defaultSource" t-ref="iframeViewerPdf"/>
+                <iframe t-if="state.thread.mainAttachment.isPdf" class="mb48" t-att-src="state.thread.mainAttachment.defaultSource" t-ref="iframeViewerPdf"/>
                 <t t-if="state.thread.attachmentsInWebClientView.length > 1">
                     <a class="arrow o_move_previous text-center" href="#" t-on-click.prevent="onClickPrevious">
                         <span class="oi oi-chevron-left"/>
diff --git a/addons/mail/static/src/discuss/attachment_model_patch.js b/addons/mail/static/src/discuss/attachment_model_patch.js
new file mode 100644
index 00000000000..2776535b8ea
--- /dev/null
+++ b/addons/mail/static/src/discuss/attachment_model_patch.js
@@ -0,0 +1,15 @@
+/* @odoo-module */
+
+import { Attachment } from "@mail/attachments/attachment_model";
+import { patch } from "@web/core/utils/patch";
+
+patch(Attachment.prototype, "discuss", {
+    get urlRoute() {
+        if (!this.accessToken && this.originThread?.model === "discuss.channel") {
+            return this.isImage
+                ? `/discuss/channel/${this.originThread.id}/image/${this.id}`
+                : `/discuss/channel/${this.originThread.id}/attachment/${this.id}`;
+        }
+        return this._super();
+    },
+});