{"id":"CVE-2026-107903","kind":"vulnerability","aliases":["CVE-2026-107903"],"related":[],"title":"Gridbox Joomla extension: stored XSS in reviews via weak sanitization","description":"Joomla Extension - balbooa.com - Stored XSS in reviews via inconsistent sanitization in Gridbox < 2.20.5.0","summary":"Gridbox, a Joomla extension from balbooa.com, stores review content without consistent sanitization, so a malicious review can carry script. The script runs in the browser of anyone who views the review, which can lead to session theft or actions taken as that user.","severity":"high","cvss":8.6,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["balbooa","gridbox","joomla","other","self-hosted"],"not_affected_if":["gridbox-not-installed","reviews-disabled"],"how_to_check":"- Check the installed Gridbox version in the Joomla extensions manager (unknown beyond that).\n- Confirm whether the reviews feature is enabled on the site.","fix":"- Gridbox versions below `2.20.5.0` are affected; move to `2.20.5.0` or later.","status":"open","published_at":"2026-11-05T18:17:00+00:00","first_seen_at":"2026-11-05T18:40:09+00:00","triaged_at":"2026-11-05T18:40:20+00:00","updated_at":"2026-11-05T18:40:20+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-05T18:40:20Z","model":"claude-haiku-5-5","output":{"fix":"- Gridbox versions below `2.20.5.0` are affected; move to `2.20.5.0` or later.","reach":"internet","title":"Gridbox Joomla extension: stored XSS in reviews via weak sanitization","impact":"medium","summary":"Gridbox, a Joomla extension from balbooa.com, stores review content without consistent sanitization, so a malicious review can carry script. The script runs in the browser of anyone who views the review, which can lead to session theft or actions taken as that user.","audience":"businesses","category":"other","nicknames":[],"who_cares":["joomla","gridbox","balbooa","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"unknown","worst_case":"script runs in visitors' browsers and can steal sessions","analyst_note":"","how_to_check":"- Check the installed Gridbox version in the Joomla extensions manager (unknown beyond that).\n- Confirm whether the reviews feature is enabled on the site.","plain_action":"","needs_analyst":false,"not_affected_if":["gridbox-not-installed","reviews-disabled"],"who_is_affected":"Joomla sites running the Gridbox extension below 2.20.5.0 that display reviews. Sites without Gridbox, or with reviews turned off, are not exposed. Whether attacks need a logged-in account is unknown from the sources.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000676,"input_tokens":4187,"output_tokens":515,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-107903':13A,16A '-2026':12A,15A '2.20.5.0':79C 'action':62B 'anyon':50B 'balbooa':17B 'balbooa.com':29B,69C 'browser':48B 'carri':41B 'consist':34B 'content':32B 'cve':11A,14A 'extens':3A,27B,68C 'gridbox':1A,18B,24B,78C 'host':23B 'inconsist':75C 'joomla':2A,19B,26B,67C 'lead':57B 'malici':38B 'review':7A,31B,39B,54B,73C 'run':45B 'sanit':10A,35B,76C 'script':42B,44B 'self':22B 'self-host':21B 'session':59B 'store':4A,30B,70C 'taken':63B 'theft':60B 'user':66B 'via':8A,74C 'view':52B 'weak':9A 'without':33B 'xss':5A,71C","nicknames":[],"mitigations":[],"who_affected":"Joomla sites running the Gridbox extension below 2.20.5.0 that display reviews. Sites without Gridbox, or with reviews turned off, are not exposed. Whether attacks need a logged-in account is unknown from the sources.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["balbooa","gridbox","high","joomla","other","selfhosted"],"campaign_type":null,"first_public_at":"2026-11-05T18:17:00+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/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":"security@joomla.org","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-107903","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107903","severity":null,"published_at":"2026-11-05T18:17:00+00:00","modified_at":"2026-11-05T18:17:00+00:00","first_seen_at":"2026-11-05T18:40:09+00:00","fetched_at":"2026-11-05T18:40:09+00:00","note":null}],"documents":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}