{"id":"CVE-2026-114722","kind":"vulnerability","aliases":["CVE-2026-114722"],"related":[],"title":"Roundcube Webmail: crafted HTML email restyles the whole interface","description":"Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by a CSS scoping bypass in HTML messages. rcube_utils::mod_css_styles() did not treat an at-rule prologue such as @layer a; as a selector boundary, and did not handle selectors beginning with ::, so selectors following an at-rule were left unscoped and applied to the whole Roundcube interface instead of being confined to the message body. This allows an HTML message to restyle application chrome for UI redressing and spoofing. Upstream fixed this in the commit “Fix CSS scoping bypass in HTML messages using at-rules”.","summary":"Roundcube did not confine CSS inside HTML emails to the message body when the CSS used an at-rule such as @layer or selectors starting with ::. A malicious message can therefore restyle Roundcube's own interface, enabling UI redressing and spoofing of login or action prompts.","severity":"medium","cvss":6.5,"epss":0.00252,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["email","package","roundcube","self-hosted","webmail"],"not_affected_if":["default-config"],"how_to_check":"- Check the installed Roundcube version in the footer, or in `program/include/iniset.php` (`RCMAIL_VERSION`), and compare it with the fixed versions below.\n- Confirm whether HTML message rendering is enabled for users (default in Roundcube).","fix":"- Upgrade Roundcube Webmail to `1.6.20` or later on the 1.6 branch, or to `1.7.5` or later on the 1.7 branch.\n- Upstream fix: commit \"Fix CSS scoping bypass in HTML messages using at-rules\".","status":"open","published_at":"2026-10-22T02:17:00+00:00","first_seen_at":"2026-10-23T21:57:30+00:00","triaged_at":"2026-10-25T03:48:46+00:00","updated_at":"2026-10-25T03:48:46+00:00","category":"package","confidence":0.8,"triage":{"at":"2026-10-25T03:48:46Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Roundcube Webmail to `1.6.20` or later on the 1.6 branch, or to `1.7.5` or later on the 1.7 branch.\n- Upstream fix: commit \"Fix CSS scoping bypass in HTML messages using at-rules\".","reach":"internet","title":"Roundcube Webmail: crafted HTML email restyles the whole interface","impact":"medium","summary":"Roundcube did not confine CSS inside HTML emails to the message body when the CSS used an at-rule such as @layer or selectors starting with ::. A malicious message can therefore restyle Roundcube's own interface, enabling UI redressing and spoofing of login or action prompts.","category":"package","nicknames":[],"who_cares":["roundcube","webmail","self-hosted","email"],"confidence":0.8,"needs_auth":"no","worst_case":"Attacker restyles the webmail interface to spoof prompts and actions","analyst_note":"","how_to_check":"- Check the installed Roundcube version in the footer, or in `program/include/iniset.php` (`RCMAIL_VERSION`), and compare it with the fixed versions below.\n- Confirm whether HTML message rendering is enabled for users (default in Roundcube).","needs_analyst":false,"not_affected_if":["default-config"],"who_is_affected":"Any Roundcube Webmail instance before 1.6.20 or in the 1.7.x line before 1.7.5 that renders HTML email, which is the default for users reading mail in the browser. Attackers only need to send a message to a user of the affected instance, so mail server operators and webmail administrators should patch. Instances that have already been upgraded, or that show only plain-text mail, are not exposed.","user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.000664,"input_tokens":3489,"output_tokens":630,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-114722':12A,15A '-2026':11A,14A '1.6.20':73C '1.7':75C '1.7.5':78C 'action':68B 'affect':80C 'allow':143C 'appli':128C 'applic':149C 'at-rul':40B,98C,121C,170C 'begin':115C 'bodi':34B,141C 'boundari':109C 'bypass':85C,165C 'chrome':150C 'commit':161C 'confin':26B,137C 'craft':3A 'css':27B,37B,83C,92C,163C 'cve':10A,13A 'email':5A,16B,30B 'enabl':60B 'fix':157C,162C 'follow':119C 'handl':113C 'host':21B 'html':4A,29B,87C,145C,167C 'insid':28B 'instead':134C 'interfac':9A,59B,133C 'layer':45B,104C 'left':125C 'login':66B 'malici':51B 'messag':33B,52B,88C,140C,146C,168C 'mod':91C 'packag':17B 'prologu':101C 'prompt':69B 'rcube':89C 'redress':62B,153C 'restyl':6A,55B,148C 'roundcub':1A,18B,23B,56B,70C,132C 'rule':42B,100C,123C,172C 'scope':84C,164C 'selector':47B,108C,114C,118C 'self':20B 'self-host':19B 'spoof':64B,155C 'start':48B 'style':93C 'therefor':54B 'treat':96C 'ui':61B,152C 'unscop':126C 'upstream':156C 'use':38B,169C 'util':90C 'webmail':2A,22B,71C 'whole':8A,131C 'x':76C","nicknames":[],"mitigations":[],"who_affected":"Any Roundcube Webmail instance before 1.6.20 or in the 1.7.x line before 1.7.5 that renders HTML email, which is the default for users reading mail in the browser. Attackers only need to send a message to a user of the affected instance, so mail server operators and webmail administrators should patch. Instances that have already been upgraded, or that show only plain-text mail, are not exposed.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T02:17:00+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":"cve@mitre.org","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-114722","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114722","severity":null,"published_at":"2026-10-22T02:17:00+00:00","modified_at":"2026-10-22T16:45:49+00:00","first_seen_at":"2026-10-23T21:57:30+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-114722","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-114722","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T07:15:52+00:00","fetched_at":"2026-10-24T07:15:52+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"}