{"id":"CVE-2026-113386","kind":"vulnerability","aliases":["CVE-2026-113386"],"related":[],"title":"Roundcube Webmail: CRLF in mail uid lets authenticated users run IMAP commands","description":"Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 are affected by IMAP command injection. A remote authenticated attacker can exploit this via CRLF sequences injected into the _uid parameter of the mail/headers and mail/viewsource actions to execute arbitrary IMAP commands.","summary":"Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 does not strip CRLF sequences from the _uid parameter of the mail/headers and mail/viewsource actions. A logged-in user can inject arbitrary IMAP commands into the mail server session, which can read or change mail beyond their own view.","severity":"high","cvss":7.1,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["imap","package","roundcube","self-hosted","webmail"],"not_affected_if":["no-untrusted-accounts","versions-already-patched"],"how_to_check":"- Check the installed Roundcube version in the footer, `CHANGELOG.md`, or `composer show roundcube/roundcubemail` where installed via Composer.\n- Confirm whether any version is below `1.6.20` on the 1.6 line or below `1.7.5` on the 1.7 line.","fix":"- Upgrade Roundcube Webmail to `1.6.20` or later on the 1.6 line, or to `1.7.5` or later on the 1.7 line.\n- Until patched, restrict who can log in to the webmail interface.","status":"open","published_at":"2026-10-20T05:16:54+00:00","first_seen_at":"2026-10-23T21:57:20+00:00","triaged_at":"2026-10-25T03:34:49+00:00","updated_at":"2026-10-25T03:34:49+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-25T03:34:49Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Roundcube Webmail to `1.6.20` or later on the 1.6 line, or to `1.7.5` or later on the 1.7 line.\n- Until patched, restrict who can log in to the webmail interface.","reach":"internet","title":"Roundcube Webmail: CRLF in mail uid lets authenticated users run IMAP commands","impact":"medium","summary":"Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 does not strip CRLF sequences from the _uid parameter of the mail/headers and mail/viewsource actions. A logged-in user can inject arbitrary IMAP commands into the mail server session, which can read or change mail beyond their own view.","category":"package","nicknames":[],"who_cares":["roundcube","webmail","self-hosted","imap"],"confidence":0.7,"needs_auth":"yes","worst_case":"Authenticated user runs arbitrary IMAP commands against the mail server","analyst_note":"","how_to_check":"- Check the installed Roundcube version in the footer, `CHANGELOG.md`, or `composer show roundcube/roundcubemail` where installed via Composer.\n- Confirm whether any version is below `1.6.20` on the 1.6 line or below `1.7.5` on the 1.7 line.","needs_analyst":false,"not_affected_if":["versions-already-patched","no-untrusted-accounts"],"who_is_affected":"Any deployment of Roundcube Webmail on the affected version ranges is exposed, since the flaw sits in the mail/headers and mail/viewsource handlers that every logged-in user reaches. Exposure needs a valid webmail account, so internet-facing instances with open or self-registration are the main concern. Installations limited to trusted internal users carry less risk but still need the upgrade.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000664,"input_tokens":3331,"output_tokens":662,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-113386':15A,18A '-2026':14A,17A '1.6.20':29B,78C '1.7':31B,80C '1.7.5':34B,83C 'action':49B,110C 'affect':85C 'arbitrari':57B,113C 'attack':93C 'authent':8A,92C 'beyond':71B 'chang':69B 'command':12A,59B,88C,115C 'crlf':3A,38B,98C 'cve':13A,16A 'execut':112C 'exploit':95C 'host':24B 'imap':11A,19B,58B,87C,114C 'inject':56B,89C,100C 'let':7A 'log':52B 'logged-in':51B 'mail':5A,62B,70B 'mail/headers':46B,107C 'mail/viewsource':48B,109C 'packag':20B 'paramet':43B,104C 'read':67B 'remot':91C 'roundcub':1A,21B,26B,75C 'run':10A 'self':23B 'self-host':22B 'sequenc':39B,99C 'server':63B 'session':64B 'strip':37B 'uid':6A,42B,103C 'user':9A,54B 'via':97C 'view':74B 'webmail':2A,25B,27B,76C 'x':32B,81C","nicknames":[],"mitigations":[],"who_affected":"Any deployment of Roundcube Webmail on the affected version ranges is exposed, since the flaw sits in the mail/headers and mail/viewsource handlers that every logged-in user reaches. Exposure needs a valid webmail account, so internet-facing instances with open or self-registration are the main concern. Installations limited to trusted internal users carry less risk but still need the upgrade.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T05:16:54+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N","cvss_by":"cve@mitre.org","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-113386","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-113386","severity":null,"published_at":"2026-10-20T05:16:54+00:00","modified_at":"2026-10-22T22:18:03+00:00","first_seen_at":"2026-10-23T21:57:20+00:00","fetched_at":"2026-10-23T22:28:57+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"}