{"id":"CVE-2026-100155","kind":"vulnerability","aliases":["CVE-2026-100155"],"related":[],"title":"Ninja Forms WordPress plugin: unauthenticated attackers can run arbitrary shortcodes","description":"The The Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder plugin for WordPress is vulnerable to arbitrary shortcode execution in all versions up to, and including, 3.15.5 This is due to the software allowing users to execute an action that does not properly validate a value before running do_shortcode. This makes it possible for unauthenticated attackers to execute arbitrary shortcodes.","summary":"The Ninja Forms contact form plugin for WordPress passes an unvalidated value to do_shortcode, so an action can be triggered that runs arbitrary shortcodes. An unauthenticated attacker can exploit this on any site running a vulnerable version, with impact depending on which shortcodes the site has available.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ninja-forms","package","self-hosted","wordpress"],"not_affected_if":["newer-version","plugin-not-installed"],"how_to_check":"- Check the installed Ninja Forms plugin version in the WordPress admin under Plugins, or with `wp plugin get ninja-forms --field=version`\n- Compare the installed version against the affected range: all versions up to and including `3.15.5`","fix":null,"status":"open","published_at":"2026-10-31T06:16:29+00:00","first_seen_at":"2026-10-31T06:33:49+00:00","triaged_at":"2026-10-31T06:34:19+00:00","updated_at":"2026-10-31T06:34:19+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-31T06:34:19Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"internet","title":"Ninja Forms WordPress plugin: unauthenticated attackers can run arbitrary shortcodes","impact":"medium","summary":"The Ninja Forms contact form plugin for WordPress passes an unvalidated value to do_shortcode, so an action can be triggered that runs arbitrary shortcodes. An unauthenticated attacker can exploit this on any site running a vulnerable version, with impact depending on which shortcodes the site has available.","audience":"businesses","category":"package","nicknames":[],"who_cares":["wordpress","ninja-forms","self-hosted"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"unauthenticated attackers run arbitrary shortcodes on the site","analyst_note":"Confirm the fixed version and the shortcodes that enable worse impact at the NVD entry https://nvd.nist.gov/vuln/detail/CVE-2026-100155 and the plugin vendor's changelog.","how_to_check":"- Check the installed Ninja Forms plugin version in the WordPress admin under Plugins, or with `wp plugin get ninja-forms --field=version`\n- Compare the installed version against the affected range: all versions up to and including `3.15.5`","plain_action":"","needs_analyst":true,"not_affected_if":["plugin-not-installed","newer-version"],"who_is_affected":"Any WordPress site with the Ninja Forms plugin installed at version 3.15.5 or earlier is exposed, because the flaw is reachable without logging in. Sites that do not run this plugin are not affected. The sources do not say which shortcodes make the impact worse or whether a fixed version exists.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000733,"input_tokens":4183,"output_tokens":630,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-100155':13A,16A '-2026':12A,15A '3.15.5':103C 'action':42B,115C 'ai':84C 'allow':110C 'arbitrari':9A,48B,93C,136C 'attack':6A,52B,133C 'avail':72B 'builder':79C,86C 'calcul':81C 'contact':28B,77C 'cve':11A,14A 'depend':65B 'due':106C 'execut':95C,113C,135C 'exploit':54B 'form':2A,19B,27B,29B,76C,78C,85C 'host':23B 'impact':64B 'includ':102C 'make':128C 'ninja':1A,18B,26B,75C 'ninja-form':17B 'packag':20B 'pass':33B 'plugin':4A,30B,87C 'possibl':130C 'proper':119C 'quizz':82C 'run':8A,47B,59B,124C 'self':22B 'self-host':21B 'shortcod':10A,39B,49B,68B,94C,126C,137C 'signatur':83C 'site':58B,70B 'softwar':109C 'trigger':45B 'unauthent':5A,51B,132C 'unvalid':35B 'user':111C 'valid':120C 'valu':36B,122C 'version':62B,98C 'vulner':61B,91C 'wordpress':3A,24B,32B,89C","nicknames":[],"mitigations":[],"who_affected":"Any WordPress site with the Ninja Forms plugin installed at version 3.15.5 or earlier is exposed, because the flaw is reachable without logging in. Sites that do not run this plugin are not affected. The sources do not say which shortcodes make the impact worse or whether a fixed version exists.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"first_public_at":"2026-10-31T06:16:29+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","cvss_by":"security@wordfence.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-100155","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100155","severity":null,"published_at":"2026-10-31T06:16:29+00:00","modified_at":"2026-10-31T06:16:29+00:00","first_seen_at":"2026-10-31T06:33:49+00:00","fetched_at":"2026-10-31T06:33:49+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"}