diff --git a/backend/__tests__/routes/adminShortUrlOwnership.test.js b/backend/__tests__/routes/adminShortUrlOwnership.test.js
new file mode 100644
index 00000000..96fe7f28
--- /dev/null
+++ b/backend/__tests__/routes/adminShortUrlOwnership.test.js
@@ -0,0 +1,151 @@
+/**
+ * GHSA-9h7q-2jpf-vj85 — DELETE /api/admin/short-urls/:id only checked
+ * `events.edit` permission, with no ownership scoping. GET and POST for an
+ * event's short URLs both chain requireEventOwnership; DELETE takes the
+ * short URL row's own :id (not :eventId), so any admin holding events.edit
+ * could delete another admin's branded gallery short URL. The route now
+ * resolves the short URL's event first and applies the same ownership
+ * predicate requireEventOwnership uses. super_admin keeps global access.
+ */
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+
+process.env.NODE_ENV = 'test';
+process.env.TEST_DATABASE_PATH = path.join(
+  fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-suown-')), 'db.sqlite',
+);
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'suown-test-secret';
+process.env.STORAGE_PATH = fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-suown-storage-'));
+
+const request = require('supertest');
+const express = require('express');
+const cookieParser = require('cookie-parser');
+const { bootCrmDb, assignAdminRole, mintAdminToken } = require('../integration/helpers/crmDb');
+
+describe('short URL delete ownership scoping', () => {
+  let db; let cleanup; let app; let service;
+  let superTok; let ownerTok; let foreignTok;
+  let ownerId;
+  let foreignShortUrlId;
+
+  const auth = (req, tok) => req.set('Authorization', `Bearer ${tok}`);
+
+  async function seedEvent(createdBy, slugSuffix) {
+    const farFuture = new Date(Date.now() + 365 * 86400000).toISOString();
+    const [id] = await db('events').insert({
+      slug: `suown-${slugSuffix}`,
+      event_type: 'wedding',
+      event_name: 'Test Event',
+      event_date: '2026-08-01',
+      host_email: 'h@e.com',
+      admin_email: 'a@e.com',
+      password_hash: 'x',
+      share_link: `suown-${slugSuffix}`,
+      share_token: `suown-share-${slugSuffix}`,
+      expires_at: farFuture,
+      is_active: true,
+      is_archived: false,
+      created_by: createdBy,
+      created_at: new Date().toISOString(),
+    });
+    return db('events').where({ id }).first();
+  }
+
+  beforeAll(async () => {
+    ({ db, cleanup } = await bootCrmDb());
+    service = require('../../src/services/galleryShortUrlService');
+
+    const superIns = await db('admin_users').insert({
+      username: 'suown-super', email: 'suown-super@example.com',
+      password_hash: 'x', must_change_password: false, created_at: new Date(),
+    }).returning('id');
+    const superId = superIns[0]?.id ?? superIns[0];
+    await assignAdminRole(db, superId, 'super_admin');
+    superTok = mintAdminToken(superId);
+
+    const ownerIns = await db('admin_users').insert({
+      username: 'suown-owner', email: 'suown-owner@example.com',
+      password_hash: 'x', must_change_password: false, created_at: new Date(),
+    }).returning('id');
+    ownerId = ownerIns[0]?.id ?? ownerIns[0];
+    await assignAdminRole(db, ownerId, 'editor');
+    ownerTok = mintAdminToken(ownerId);
+
+    const foreignIns = await db('admin_users').insert({
+      username: 'suown-foreign', email: 'suown-foreign@example.com',
+      password_hash: 'x', must_change_password: false, created_at: new Date(),
+    }).returning('id');
+    const foreignId = foreignIns[0]?.id ?? foreignIns[0];
+    await assignAdminRole(db, foreignId, 'editor');
+    foreignTok = mintAdminToken(foreignId);
+
+    // Event owned by `owner`, NOT `foreign`.
+    await seedEvent(ownerId, 'owned');
+
+    app = express();
+    app.use(express.json());
+    app.use(cookieParser());
+    app.use('/api/admin', require('../../src/routes/adminShortUrls'));
+  }, 120000);
+
+  afterAll(async () => { if (cleanup) await cleanup(); });
+
+  beforeEach(async () => {
+    // Fresh short URL per DELETE test so earlier deletes don't interfere.
+    const event = await db('events').where({ created_by: ownerId }).first();
+    const row = await service.createShortUrl({
+      eventId: event.id,
+      customSlug: `suown-target-${Date.now()}-${Math.random().toString(36).slice(2, 6)}`,
+      createdBy: ownerId,
+    });
+    foreignShortUrlId = row.id;
+  });
+
+  it('an admin who does not own the event cannot delete its short URL (403, row survives)', async () => {
+    const res = await auth(
+      request(app).delete(`/api/admin/short-urls/${foreignShortUrlId}`),
+      foreignTok,
+    );
+    expect(res.status).toBe(403);
+    const row = await db('gallery_short_urls').where({ id: foreignShortUrlId }).first();
+    expect(row).toBeDefined();
+    expect(row.deleted_at).toBeFalsy();
+  });
+
+  it('the owning admin can delete its own short URL', async () => {
+    const res = await auth(
+      request(app).delete(`/api/admin/short-urls/${foreignShortUrlId}`),
+      ownerTok,
+    );
+    expect(res.status).toBe(204);
+    const row = await db('gallery_short_urls').where({ id: foreignShortUrlId }).first();
+    expect(row.deleted_at).toBeTruthy();
+  });
+
+  it('super_admin can delete any short URL', async () => {
+    const res = await auth(
+      request(app).delete(`/api/admin/short-urls/${foreignShortUrlId}`),
+      superTok,
+    );
+    expect(res.status).toBe(204);
+    const row = await db('gallery_short_urls').where({ id: foreignShortUrlId }).first();
+    expect(row.deleted_at).toBeTruthy();
+  });
+
+  it('deleting a nonexistent short URL id returns 404', async () => {
+    const res = await auth(
+      request(app).delete('/api/admin/short-urls/9999999'),
+      superTok,
+    );
+    expect(res.status).toBe(404);
+  });
+
+  it('deleting a nonexistent short URL id as a non-owner also returns 404 (existence check runs first)', async () => {
+    const res = await auth(
+      request(app).delete('/api/admin/short-urls/9999999'),
+      foreignTok,
+    );
+    expect(res.status).toBe(404);
+  });
+});
diff --git a/backend/src/routes/adminShortUrls.js b/backend/src/routes/adminShortUrls.js
index 518d4779..0e37eab4 100644
--- a/backend/src/routes/adminShortUrls.js
+++ b/backend/src/routes/adminShortUrls.js
@@ -15,6 +15,7 @@ const { safeValidationErrors } = require('../utils/routeHelpers');
 const { adminAuth } = require('../middleware/auth');
 const { requirePermission } = require('../middleware/permissions');
 const { requireEventOwnership } = require('../middleware/ownership');
+const { db } = require('../database/db');
 const galleryShortUrlService = require('../services/galleryShortUrlService');
 const logger = require('../utils/logger');
 
@@ -86,6 +87,31 @@ router.post(
   },
 );
 
+/**
+ * Ownership guard for the by-short-url-id DELETE route (GHSA-9h7q-2jpf-vj85).
+ * GET/POST take :eventId directly so requireEventOwnership applies as-is;
+ * DELETE takes the short URL row's own :id, so resolve its event first and
+ * apply the same ownership predicate requireEventOwnership uses (event has
+ * no owner, or the admin owns it). Sends the response and returns false
+ * when the caller may not act on it (404 if the row doesn't exist, 403 if
+ * it exists but belongs to another admin).
+ */
+async function assertOwnsShortUrl(req, res, id) {
+  const row = await db('gallery_short_urls').where({ id }).first('event_id');
+  if (!row) {
+    res.status(404).json({ error: 'Short URL not found' });
+    return false;
+  }
+  if (req.admin.roleName !== 'super_admin') {
+    const event = await db('events').where({ id: row.event_id }).first('created_by');
+    if (event && event.created_by && event.created_by !== req.admin.id) {
+      res.status(403).json({ error: 'Access denied' });
+      return false;
+    }
+  }
+  return true;
+}
+
 /**
  * DELETE /api/admin/short-urls/:id
  * Soft-delete. The public route serves 410 Gone on a deleted row so the
@@ -99,10 +125,9 @@ router.delete(
     const errors = validationResult(req);
     if (!errors.isEmpty()) return res.status(400).json({ errors: safeValidationErrors(errors) });
     try {
-      const ok = await galleryShortUrlService.softDelete(
-        parseInt(req.params.id, 10),
-        req.admin?.id || null,
-      );
+      const id = parseInt(req.params.id, 10);
+      if (!(await assertOwnsShortUrl(req, res, id))) return;
+      const ok = await galleryShortUrlService.softDelete(id, req.admin?.id || null);
       if (!ok) return res.status(404).json({ error: 'Short URL not found' });
       res.status(204).end();
     } catch (err) {