{"id":"CVE-2026-121551","kind":"vulnerability","aliases":["CVE-2026-121551"],"related":[],"title":"PostfixAdmin: stored XSS in TOTP exception description runs in admin session","description":"PostfixAdmin through 4.0.5 contains a stored cross-site scripting vulnerability that allows authenticated mailbox users to inject script by creating a TOTP exception with an unescaped description. When a global administrator views totp-exceptions.php, the script runs in the admin session and can issue authenticated admin requests using the page's CSRF token.","summary":"PostfixAdmin through 4.0.5 does not escape the description field of a TOTP exception, so a logged-in mailbox user can store script that runs when a global administrator opens totp-exceptions.php. The script runs in the admin's session and can send authenticated admin requests using the page's CSRF token.","severity":"medium","cvss":5.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["mail-server","package","postfixadmin","self-hosted"],"not_affected_if":["no-mailbox-users-on-admin-instance","totp-exceptions-unused"],"how_to_check":"- Check the installed PostfixAdmin version against the product range `through 4.0.5`\n- Look for TOTP exception support in the admin area (totp-exceptions.php)","fix":"- PostfixAdmin: fixed version unknown from the sources; a patch link is listed in the advisory references","status":"open","published_at":"2026-11-03T16:17:27+00:00","first_seen_at":"2026-11-03T16:21:44+00:00","triaged_at":"2026-11-03T16:24:14+00:00","updated_at":"2026-11-03T16:24:14+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-03T16:24:14Z","model":"claude-haiku-5-5","output":{"fix":"- PostfixAdmin: fixed version unknown from the sources; a patch link is listed in the advisory references","reach":"network","title":"PostfixAdmin: stored XSS in TOTP exception description runs in admin session","impact":"high","summary":"PostfixAdmin through 4.0.5 does not escape the description field of a TOTP exception, so a logged-in mailbox user can store script that runs when a global administrator opens totp-exceptions.php. The script runs in the admin's session and can send authenticated admin requests using the page's CSRF token.","audience":"businesses","category":"package","nicknames":[],"who_cares":["postfixadmin","mail-server","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"yes","worst_case":"script runs in admin session and issues admin requests","analyst_note":"Confirm the fixed version and the patch commit from the linked GitHub patch and the VulnCheck advisory.","how_to_check":"- Check the installed PostfixAdmin version against the product range `through 4.0.5`\n- Look for TOTP exception support in the admin area (totp-exceptions.php)\n- unknown for further checks","plain_action":"","needs_analyst":true,"not_affected_if":["no-mailbox-users-on-admin-instance","totp-exceptions-unused"],"who_is_affected":"Sites running PostfixAdmin 4.0.5 or earlier where mailbox users can create TOTP exceptions and global administrators open the TOTP exceptions page. The attacker needs a mailbox account on the instance; skip this if the admin interface is not exposed to mailbox users.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000719,"input_tokens":4182,"output_tokens":601,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-121551':14A,17A '-2026':13A,16A '4.0.5':28B,79C 'admin':10A,62B,69B,116C,122C 'administr':54B,108C 'allow':89C 'authent':68B,90C,121C 'contain':80C 'creat':97C 'cross':84C 'cross-sit':83C 'csrf':75B,128C 'cve':12A,15A 'descript':7A,33B,104C 'escap':31B 'except':6A,38B,100C 'field':34B 'global':53B,107C 'host':25B 'inject':94C 'issu':120C 'log':42B 'logged-in':41B 'mail':19B 'mail-serv':18B 'mailbox':44B,91C 'open':55B 'packag':21B 'page':73B,126C 'postfixadmin':1A,22B,26B,77C 'request':70B,123C 'run':8A,50B,59B,113C 'script':48B,58B,86C,95C,112C 'self':24B 'self-host':23B 'send':67B 'server':20B 'session':11A,64B,117C 'site':85C 'store':2A,47B,82C 'token':76B,129C 'totp':5A,37B,99C 'totp-exceptions.php':56B,110C 'unescap':103C 'use':71B,124C 'user':45B,92C 'view':109C 'vulner':87C 'xss':3A","nicknames":[],"mitigations":[],"who_affected":"Sites running PostfixAdmin 4.0.5 or earlier where mailbox users can create TOTP exceptions and global administrators open the TOTP exceptions page. The attacker needs a mailbox account on the instance; skip this if the admin interface is not exposed to mailbox users.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["mailserver","medium","package","postfixadmin","selfhosted"],"campaign_type":null,"first_public_at":"2026-11-03T16:17:27+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/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-2026-121551","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121551","severity":null,"published_at":"2026-11-03T16:17:27+00:00","modified_at":"2026-11-03T16:17:27+00:00","first_seen_at":"2026-11-03T16:21:44+00:00","fetched_at":"2026-11-03T16:21:44+00:00","note":null}],"documents":[{"id":58838,"url":"https://github.com/postfixadmin/postfixadmin/commit/0a894b08769481ce1a7f0f42af901c6d9f88fa9c","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":58839,"url":"https://www.vulncheck.com/advisories/postfixadmin-through-4.0.5-stored-xss-via-totp-exception-description","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}