{"id":"CVE-2026-116871","kind":"vulnerability","aliases":["CVE-2026-116871"],"related":[],"title":"Semantic MediaWiki: unauthenticated nested queries exhaust CPU and memory","description":"Semantic MediaWiki 3.0.0 before 7.3.1 contains an uncontrolled recursion vulnerability in LegacyParser::getSubqueryDescription() that processes nested query tokens before depth limits apply. Unauthenticated attackers can submit deeply nested query elements to the action=ask API to consume substantial CPU and memory, tying up request workers.","summary":"Semantic MediaWiki 3.0.0 before 7.3.1 recurses without a depth limit when parsing nested query tokens in LegacyParser::getSubqueryDescription(). An unauthenticated attacker can send deeply nested queries to the action=ask API to consume CPU and memory and tie up request workers, causing denial of service.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["mediawiki","package","self-hosted","semantic-mediawiki"],"not_affected_if":["version-7.3.1-or-later"],"how_to_check":"- Check the installed Semantic MediaWiki version in Special:Version or in composer.lock for `mediawiki/semantic-media-wiki`, and see whether it is `3.0.0` through `7.3.0`.\n- Confirm whether the wiki exposes the action=ask API to anonymous users.","fix":"- Upgrade Semantic MediaWiki to `7.3.1` or later.","status":"open","published_at":"2026-10-27T11:17:28+00:00","first_seen_at":"2026-10-27T11:31:27+00:00","triaged_at":"2026-10-27T11:31:42+00:00","updated_at":"2026-10-27T11:31:42+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-27T11:31:42Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Semantic MediaWiki to `7.3.1` or later.","reach":"internet","title":"Semantic MediaWiki: unauthenticated nested queries exhaust CPU and memory","impact":"low","summary":"Semantic MediaWiki 3.0.0 before 7.3.1 recurses without a depth limit when parsing nested query tokens in LegacyParser::getSubqueryDescription(). An unauthenticated attacker can send deeply nested queries to the action=ask API to consume CPU and memory and tie up request workers, causing denial of service.","category":"package","nicknames":[],"who_cares":["mediawiki","semantic-mediawiki","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Unauthenticated requests exhaust CPU and memory, causing wiki outage","analyst_note":"","how_to_check":"- Check the installed Semantic MediaWiki version in Special:Version or in composer.lock for `mediawiki/semantic-media-wiki`, and see whether it is `3.0.0` through `7.3.0`.\n- Confirm whether the wiki exposes the action=ask API to anonymous users.","needs_analyst":false,"not_affected_if":["version-7.3.1-or-later"],"who_is_affected":"Wikis running Semantic MediaWiki from 3.0.0 up to but not including 7.3.1 that serve the action=ask API to unauthenticated visitors are exposed. Sites that are on 7.3.1 or later, or that restrict the API to logged-in users, are less exposed. The sources do not say whether other configurations change exposure.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000635,"input_tokens":3348,"output_tokens":600,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-116871':12A,15A '-2026':11A,14A '3.0.0':26B,71C '7.3.1':28B,73C 'action':52B,101C 'api':54B,103C 'appli':90C 'ask':53B,102C 'attack':44B,92C 'caus':65B 'consum':56B,105C 'contain':74C 'cpu':7A,57B,107C 'cve':10A,13A 'deepli':47B,95C 'denial':66B 'depth':32B,88C 'element':98C 'exhaust':6A 'getsubquerydescript':41B,81C 'host':20B 'legacypars':40B,80C 'limit':33B,89C 'mediawiki':2A,16B,23B,25B,70C 'memori':9A,59B,109C 'nest':4A,36B,48B,84C,96C 'packag':17B 'pars':35B 'process':83C 'queri':5A,37B,49B,85C,97C 'recurs':29B,77C 'request':63B,112C 'self':19B 'self-host':18B 'semant':1A,22B,24B,69C 'semantic-mediawiki':21B 'send':46B 'servic':68B 'submit':94C 'substanti':106C 'tie':61B,110C 'token':38B,86C 'unauthent':3A,43B,91C 'uncontrol':76C 'vulner':78C 'without':30B 'worker':64B,113C","nicknames":[],"mitigations":[],"who_affected":"Wikis running Semantic MediaWiki from 3.0.0 up to but not including 7.3.1 that serve the action=ask API to unauthenticated visitors are exposed. Sites that are on 7.3.1 or later, or that restrict the API to logged-in users, are less exposed. The sources do not say whether other configurations change exposure.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T11:17:28+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-116871","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-116871","severity":null,"published_at":"2026-10-27T11:17:28+00:00","modified_at":"2026-10-27T11:17:28+00:00","first_seen_at":"2026-10-27T11:31:27+00:00","fetched_at":"2026-10-27T11:31:27+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"}