{"id":"CVE-2026-96660","kind":"vulnerability","aliases":["CVE-2026-96660"],"related":[],"title":"WordPress User Registration plugin: unauthenticated stored XSS via checkbox field","description":"The User Registration & Membership – Free & Paid Memberships, Subscriptions, Content Restriction, User Profile, Custom User Registration & Login Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Checkbox Field Value in all versions up to, and including, 5.2.8 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The nopriv AJAX action user_registration_user_form_submit reaches ur_process_registration() without nonce validation, meaning any unauthenticated request can reach the vulnerable code path.","summary":"The User Registration & Membership WordPress plugin up to and including 5.2.8 does not sanitize or escape checkbox field values. An unauthenticated attacker can store a script that runs in the browser of any user who opens the injected page.","severity":"high","cvss":7.2,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","self-hosted","wordpress","wordpress-plugin"],"not_affected_if":["plugin-not-installed","version-above-5.2.8"],"how_to_check":"- Check the installed version of the User Registration & Membership plugin in the WordPress admin Plugins screen, or with `wp plugin get user-registration --field=version`\n- Confirm the version is `5.2.8` or lower to be exposed","fix":"- Update the User Registration & Membership plugin to a version later than `5.2.8` once the vendor publishes a fixed release (unknown from sources)\n- Until patched, consider disabling the plugin or restricting its registration form endpoint at the web server","status":"open","published_at":"2026-10-17T04:17:10+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","triaged_at":"2026-10-25T03:29:28+00:00","updated_at":"2026-10-25T03:29:28+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-25T03:29:28Z","model":"claude-haiku-5-5","output":{"fix":"- Update the User Registration & Membership plugin to a version later than `5.2.8` once the vendor publishes a fixed release (unknown from sources)\n- Until patched, consider disabling the plugin or restricting its registration form endpoint at the web server","reach":"internet","title":"WordPress User Registration plugin: unauthenticated stored XSS via checkbox field","impact":"medium","summary":"The User Registration & Membership WordPress plugin up to and including 5.2.8 does not sanitize or escape checkbox field values. An unauthenticated attacker can store a script that runs in the browser of any user who opens the injected page.","category":"package","nicknames":[],"who_cares":["wordpress","wordpress-plugin","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Attacker script runs in visitors' and admins' browsers on injected pages.","analyst_note":"Confirm the patched version and any vendor fix from the NVD entry at https://nvd.nist.gov/vuln/detail/CVE-2026-96660.","how_to_check":"- Check the installed version of the User Registration & Membership plugin in the WordPress admin Plugins screen, or with `wp plugin get user-registration --field=version`\n- Confirm the version is `5.2.8` or lower to be exposed","needs_analyst":true,"not_affected_if":["plugin-not-installed","version-above-5.2.8"],"who_is_affected":"Sites running the User Registration & Membership plugin at version 5.2.8 or lower are exposed, since the registration form submit path accepts unauthenticated requests without nonce checks. Any page that renders the stored checkbox value can deliver the script to visitors, including logged-in administrators. Sites without this plugin installed are not affected.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000668,"input_tokens":3455,"output_tokens":645,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':12A,15A '-96660':13A,16A '5.2.8':35B,103C 'access':132C 'action':139C 'ajax':138C 'arbitrari':121C 'attack':46B,118C 'browser':55B 'builder':80C 'checkbox':9A,41B,93C 'code':160C 'content':72C 'cross':89C 'cross-sit':88C 'custom':76C 'cve':11A,14A 'due':104C 'escap':40B,111C 'execut':128C 'field':10A,42B,94C 'form':143C 'free':68C 'host':20B 'includ':34B,102C 'inject':62B,120C,134C 'input':107C 'insuffici':106C 'login':79C 'make':113C 'mean':152C 'membership':28B,67C,70C 'nonc':150C 'nopriv':137C 'open':60B 'output':110C 'packag':17B 'page':63B,125C,135C 'paid':69C 'path':161C 'plugin':4A,24B,30B,81C 'possibl':115C 'process':147C 'profil':75C 'reach':145C,157C 'registr':3A,27B,66C,78C,141C,148C 'request':155C 'restrict':73C 'run':52B 'sanit':38B,108C 'script':50B,91C,123C 'self':19B 'self-host':18B 'site':90C 'store':6A,48B,87C 'submit':144C 'subscript':71C 'unauthent':5A,45B,117C,154C 'ur':146C 'user':2A,26B,58B,65C,74C,77C,131C,140C,142C 'valid':151C 'valu':43B,95C 'version':98C 'via':8A,92C 'vulner':85C,159C 'web':122C 'whenev':129C 'without':149C 'wordpress':1A,21B,23B,29B,83C 'wordpress-plugin':22B 'xss':7A","nicknames":[],"mitigations":[],"who_affected":"Sites running the User Registration & Membership plugin at version 5.2.8 or lower are exposed, since the registration form submit path accepts unauthenticated requests without nonce checks. Any page that renders the stored checkbox value can deliver the script to visitors, including logged-in administrators. Sites without this plugin installed are not affected.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-17T04:17:10+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N","cvss_by":"security@wordfence.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-96660","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-96660","severity":null,"published_at":"2026-10-17T04:17:10+00:00","modified_at":"2026-10-19T15:16:45+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","fetched_at":"2026-10-23T22:28:55+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}