{"id":"CVE-2026-113869","kind":"vulnerability","aliases":["CVE-2026-113869"],"related":[],"title":"Thunderbird: S/MIME decryption prompt race causes use-after-free crash","description":"When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a potentially exploitable crash. This vulnerability was fixed in Thunderbird 158.0.1.","summary":"When Thunderbird asks for a security device password (such as a smartcard PIN or Primary Password) while decrypting an S/MIME message, cancelling or finishing the load frees the message decoder while it is still in use. The resulting use-after-free can crash Thunderbird in a way that may be exploitable for code execution.","severity":"medium","cvss":5.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["desktop","package","s-mime","thunderbird"],"not_affected_if":["no-s-mime","no-smartcard-or-primary-password"],"how_to_check":"- Run `thunderbird --version` (or check Help > About Thunderbird) and compare against the fixed release `158.0.1`.\n- Confirm whether S/MIME is used: Account Settings > End-to-End Encryption lists S/MIME certificates.","fix":"- Update Thunderbird to `158.0.1` or later.","status":"open","published_at":"2026-10-20T20:17:19+00:00","first_seen_at":"2026-10-23T21:57:21+00:00","triaged_at":"2026-10-25T04:16:28+00:00","updated_at":"2026-10-25T04:16:28+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T04:16:28Z","model":"claude-haiku-5-5","output":{"fix":"- Update Thunderbird to `158.0.1` or later.","reach":"internet","title":"Thunderbird: S/MIME decryption prompt race causes use-after-free crash","impact":"medium","summary":"When Thunderbird asks for a security device password (such as a smartcard PIN or Primary Password) while decrypting an S/MIME message, cancelling or finishing the load frees the message decoder while it is still in use. The resulting use-after-free can crash Thunderbird in a way that may be exploitable for code execution.","category":"package","nicknames":[],"who_cares":["thunderbird","desktop","s-mime"],"confidence":0.6,"needs_auth":"no","worst_case":"Thunderbird crashes, with a possibly exploitable memory corruption","analyst_note":"","how_to_check":"- Run `thunderbird --version` (or check Help > About Thunderbird) and compare against the fixed release `158.0.1`.\n- Confirm whether S/MIME is used: Account Settings > End-to-End Encryption lists S/MIME certificates.","needs_analyst":false,"not_affected_if":["no-s-mime","no-smartcard-or-primary-password"],"who_is_affected":"Users of Thunderbird who read S/MIME encrypted mail and use a smartcard or a Primary Password that prompts during decryption. Installations that do not use S/MIME or a security device prompt are not in the described trigger path. The sources do not say whether the crash is reachable from a remote message without user action.","user_interaction":"yes","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.00061,"input_tokens":3340,"output_tokens":552,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-113869':14A,17A '-2026':13A,16A '158.0.1':142C 'ask':26B,81C 'cancel':45B,108C 'caus':6A,125C 'code':77B 'could':104C 'crash':11A,67B,135C 'cve':12A,15A 'decod':53B,118C 'decrypt':3A,41B,97C 'desktop':18B 'devic':30B,85C 'exampl':88C 'execut':78B 'exploit':75B,134C 'finish':47B,105C 'fix':139C 'free':10A,50B,65B,130C 'freed':115C 'load':49B,103C 'may':73B 'messag':44B,52B,100C,102C,117C 'mime':22B 'open':113C 'packag':19B 'password':31B,39B,86C,95C 'pin':36B,91C 'potenti':133C 'primari':38B,94C 'prompt':4A,111C 'race':5A 'result':61B 's-mime':20B 's/mime':2A,43B,99C 'secur':29B,84C 'smartcard':35B,90C 'still':57B,122C 'thunderbird':1A,23B,25B,68B,80C,141C 'use':8A,59B,63B,124C,128C 'use-after-fre':7A,62B,127C 'vulner':137C 'way':71B","nicknames":[],"mitigations":[],"who_affected":"Users of Thunderbird who read S/MIME encrypted mail and use a smartcard or a Primary Password that prompts during decryption. Installations that do not use S/MIME or a security device prompt are not in the described trigger path. The sources do not say whether the crash is reachable from a remote message without user action.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T20:17:19+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L","cvss_by":"134c704f-9b21-4f2e-91b3-4a467353bcc0","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-113869","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-113869","severity":null,"published_at":"2026-10-20T20:17:19+00:00","modified_at":"2026-10-22T17:36:46+00:00","first_seen_at":"2026-10-23T21:57:21+00:00","fetched_at":"2026-10-23T22:28:58+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"}