{"id":"CVE-2026-118174","kind":"vulnerability","aliases":["CVE-2026-118174"],"related":[],"title":"Thunderbird: OpenPGP key attachments leak requests and NTLM credentials on display","description":"When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key. A sender could mark the attachment as an external attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction, bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share could leak the user's NTLM credentials.\nThe NTLM credential leak only affects Thunderbird on Windows. On other operating systems, the issue allowed a remote request that bypassed remote content blocking. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.","summary":"Thunderbird automatically fetched an external OpenPGP key attachment when a message was displayed, even with remote content blocking on. A sender can point that attachment at any URL, so opening the mail sends a request that can leak the user's NTLM credentials on Windows.","severity":"medium","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["desktop-mail","package","thunderbird","windows"],"not_affected_if":["fixed-version","webmail-only"],"how_to_check":"- Run Help > About Thunderbird and compare the version with `153.6.0` or `159.0`\n- Check whether the installed version is below `153.6` on the 153 branch or below `159` on newer branches","fix":"- Update Thunderbird to `159` or `153.6` or later, the versions named in the advisory","status":"open","published_at":"2026-10-27T19:17:29+00:00","first_seen_at":"2026-10-27T19:33:18+00:00","triaged_at":"2026-10-27T19:35:13+00:00","updated_at":"2026-10-27T19:35:13+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-27T19:35:13Z","model":"claude-haiku-5-5","output":{"fix":"- Update Thunderbird to `159` or `153.6` or later, the versions named in the advisory","reach":"internet","title":"Thunderbird: OpenPGP key attachments leak requests and NTLM credentials on display","impact":"medium","summary":"Thunderbird automatically fetched an external OpenPGP key attachment when a message was displayed, even with remote content blocking on. A sender can point that attachment at any URL, so opening the mail sends a request that can leak the user's NTLM credentials on Windows.","category":"package","nicknames":[],"who_cares":["thunderbird","windows","desktop-mail"],"confidence":0.7,"needs_auth":"no","worst_case":"Remote request sent on open; NTLM credentials leaked on Windows","analyst_note":"Sources list only NVD; confirm the exact affected version range and any advisory text from mozilla.org security advisories.","how_to_check":"- Run Help > About Thunderbird and compare the version with `153.6.0` or `159.0`\n- Check whether the installed version is below `153.6` on the 153 branch or below `159` on newer branches","needs_analyst":true,"not_affected_if":["fixed-version","webmail-only"],"who_is_affected":"Anyone who reads mail in Thunderbird with an OpenPGP key attachment open-on-display, so any Thunderbird install on the mail path. The NTLM credential leak applies to Windows installs; other platforms get an unblocked remote request. Teams that read mail only in a webmail client or with the update already applied can skip it.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.000626,"input_tokens":3437,"output_tokens":565,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-118174':14A,17A '-2026':13A,16A '153.6':170C '159':167C 'affect':142C 'allow':152C 'arbitrari':104C 'attach':4A,31B,48B,76C,83C,96C,100C 'attack':126C 'attacker-control':125C 'automat':25B,80C 'block':41B,117C,160C 'bypass':114C,157C 'contain':72C 'content':40B,85C,116C,159C 'control':127C 'could':93C,130C 'credenti':9A,66B,136C,139C 'cve':12A,15A 'desktop':19B 'desktop-mail':18B 'display':11A,36B,78C 'even':37B 'extern':28B,99C 'fetch':26B 'fix':164C 'import':88C 'interact':113C 'issu':151C 'key':3A,30B,75C,90C 'leak':5A,61B,131C,140C 'load':81C,109C 'mail':20B,55B 'mark':94C 'messag':34B,71C 'network':128C 'ntlm':8A,65B,135C,138C 'offer':87C 'open':53B 'openpgp':2A,29B,74C 'oper':148C 'packag':21B 'point':46B,101C,122C 'remot':39B,115C,154C,158C 'request':6A,58B,155C 'send':56B 'sender':44B,92C 'share':129C 'system':149C 'thunderbird':1A,22B,24B,79C,107C,143C,166C,169C 'url':51B,105C,121C 'user':63B,112C,133C 'vulner':162C 'window':23B,68B,119C,145C 'without':110C","nicknames":[],"mitigations":[],"who_affected":"Anyone who reads mail in Thunderbird with an OpenPGP key attachment open-on-display, so any Thunderbird install on the mail path. The NTLM credential leak applies to Windows installs; other platforms get an unblocked remote request. Teams that read mail only in a webmail client or with the update already applied can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T19:17:29+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-118174","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118174","severity":null,"published_at":"2026-10-27T19:17:29+00:00","modified_at":"2026-10-27T19:17:29+00:00","first_seen_at":"2026-10-27T19:33:18+00:00","fetched_at":"2026-10-27T19:33:18+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"}