{"id":"CVE-2026-127121","kind":"vulnerability","aliases":["CVE-2026-127121"],"related":[],"title":"SOGo: forged signed email replaces a contact's S/MIME certificate","description":"SOGo before 5.12.13 contains an improper cryptographic signature verification vulnerability that allows remote attackers to replace a victim's contact S/MIME certificate by sending a spoofed multipart/signed message with a mismatched signature and an impersonated From address. Attackers can deliver a crafted CMS signedData object containing their own self-signed certificate, which SOGo's UIxMailView stores on the contact card without validating signature authenticity or certificate identity, enabling subsequent encrypted communications to be decrypted with the attacker's private key.","summary":"SOGo, a groupware server for mail, calendars and contacts, accepts a spoofed signed email and stores the attacker's self-signed certificate on the victim's contact card without checking the signature. Later encrypted mail to that contact can be decrypted with the attacker's private key.","severity":"high","cvss":7.1,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["email","other","self-hosted","smime","sogo"],"not_affected_if":["no-smime-use"],"how_to_check":"- Check the installed SOGo version against the fixed version below.","fix":"- SOGo: `5.12.13` or later (per the vulnerability description: before 5.12.13 is affected)","status":"open","published_at":"2026-11-12T16:19:07+00:00","first_seen_at":"2026-11-12T16:44:02+00:00","triaged_at":"2026-11-12T16:45:41+00:00","updated_at":"2026-11-12T16:45:41+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-12T16:45:41Z","model":"claude-haiku-5-5","output":{"fix":"- SOGo: `5.12.13` or later (per the vulnerability description: before 5.12.13 is affected)","reach":"internet","title":"SOGo: forged signed email replaces a contact's S/MIME certificate","impact":"high","summary":"SOGo, a groupware server for mail, calendars and contacts, accepts a spoofed signed email and stores the attacker's self-signed certificate on the victim's contact card without checking the signature. Later encrypted mail to that contact can be decrypted with the attacker's private key.","audience":"businesses","category":"other","nicknames":[],"who_cares":["sogo","self-hosted","smime","email"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"attacker decrypts later encrypted mail sent to victim contacts","analyst_note":"Confirm affected SOGo versions and whether S/MIME must be enabled, using the NVD and release notes pages linked in the sources.","how_to_check":"- Check the installed SOGo version against the fixed version below.\n- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-smime-use"],"who_is_affected":"SOGo servers that receive S/MIME signed mail and let users store S/MIME certificates on contact cards are exposed to certificate replacement. Installations without S/MIME use or with mail handled elsewhere can likely skip it; the sources do not say more.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.00073,"input_tokens":4669,"output_tokens":527,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-127121':13A,16A '-2026':12A,15A '5.12.13':74C 'accept':33B 'address':108C 'allow':83C 'attack':41B,68B,85C,109C,149C 'authent':136C 'calendar':30B 'card':52B,132C 'certif':10A,46B,93C,123C,138C 'check':54B 'cms':114C 'communic':143C 'contact':7A,32B,51B,62B,91C,131C 'contain':75C,117C 'craft':113C 'cryptograph':78C 'cve':11A,14A 'decrypt':65B,146C 'deliv':111C 'email':4A,17B,37B 'enabl':140C 'encrypt':58B,142C 'forg':2A 'groupwar':26B 'host':21B 'ident':139C 'imperson':106C 'improp':77C 'key':71B,152C 'later':57B 'mail':29B,59B 'messag':99C 'mismatch':102C 'multipart/signed':98C 'object':116C 'privat':70B,151C 'remot':84C 'replac':5A,87C 's/mime':9A,92C 'self':20B,44B,121C 'self-host':19B 'self-sign':43B,120C 'send':95C 'server':27B 'sign':3A,36B,45B,122C 'signatur':56B,79C,103C,135C 'signeddata':115C 'smime':22B 'sogo':1A,23B,24B,72C,125C 'spoof':35B,97C 'store':39B,128C 'subsequ':141C 'uixmailview':127C 'valid':134C 'verif':80C 'victim':49B,89C 'vulner':81C 'without':53B,133C","nicknames":[],"mitigations":[],"who_affected":"SOGo servers that receive S/MIME signed mail and let users store S/MIME certificates on contact cards are exposed to certificate replacement. Installations without S/MIME use or with mail handled elsewhere can likely skip it; the sources do not say more.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["email","high","other","selfhosted","smime","sogo"],"campaign_type":null,"search_a":"'-127121':13A,16A '-2026':12A,15A 'certif':10A 'contact':7A 'cve':11A,14A 'email':4A 'forg':2A 'replac':5A 's/mime':9A 'sign':3A 'sogo':1A","search_b":"'accept':33B 'attack':41B,68B 'calendar':30B 'card':52B 'certif':46B 'check':54B 'contact':32B,51B,62B 'decrypt':65B 'email':17B,37B 'encrypt':58B 'groupwar':26B 'host':21B 'key':71B 'later':57B 'mail':29B,59B 'privat':70B 'self':20B,44B 'self-host':19B 'self-sign':43B 'server':27B 'sign':36B,45B 'signatur':56B 'smime':22B 'sogo':23B,24B 'spoof':35B 'store':39B 'victim':49B 'without':53B","search_c":"'5.12.13':74C 'address':108C 'allow':83C 'attack':85C,109C,149C 'authent':136C 'card':132C 'certif':93C,123C,138C 'cms':114C 'communic':143C 'contact':91C,131C 'contain':75C,117C 'craft':113C 'cryptograph':78C 'decrypt':146C 'deliv':111C 'enabl':140C 'encrypt':142C 'ident':139C 'imperson':106C 'improp':77C 'key':152C 'messag':99C 'mismatch':102C 'multipart/signed':98C 'object':116C 'privat':151C 'remot':84C 'replac':87C 's/mime':92C 'self':121C 'self-sign':120C 'send':95C 'sign':122C 'signatur':79C,103C,135C 'signeddata':115C 'sogo':72C,125C 'spoof':97C 'store':128C 'subsequ':141C 'uixmailview':127C 'valid':134C 'verif':80C 'victim':89C 'vulner':81C 'without':133C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-12T16:19:07+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/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-2026-127121","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-127121","severity":null,"published_at":"2026-11-12T16:19:07+00:00","modified_at":"2026-11-12T16:19:07+00:00","first_seen_at":"2026-11-12T16:44:02+00:00","fetched_at":"2026-11-12T16:44:02+00:00","note":null}],"documents":[{"id":136541,"url":"https://github.com/Alinto/sogo/releases/tag/SOGo-5.12.13","title":"Release notes: github.com","kind":"release","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Release notes: github.com"},{"id":136544,"url":"https://www.vulncheck.com/advisories/sogo-before-s-mime-certificate-spoofing-via-uixmailview","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"}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}