{"id":"CVE-2019-11707","kind":"vulnerability","aliases":["CVE-2019-11707"],"related":[],"title":"Mozilla Firefox and Thunderbird: Mozilla Firefox and Thunderbird Type Confusion Vulnerability","description":"A type confusion vulnerability can occur when manipulating JavaScript objects due to issues in Array.pop. This can allow for an exploitable crash. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 60.7.1, Firefox < 67.0.3, and Thunderbird < 60.7.2.","summary":"Mozilla Firefox and Thunderbird have a type confusion bug in the JavaScript Array.pop handling, reachable by manipulating JavaScript objects. An attacker who lures a user to a crafted page can cause a crash and, per the CISA listing, the flaw is known to be exploited in the wild.","severity":"high","cvss":8.8,"epss":0.37696,"exploited":true,"exploited_at":"2022-05-23T00:00:00+00:00","products":[{"name":"Mozilla Firefox and Thunderbird","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["browser","desktop","exploited","firefox","package","thunderbird"],"not_affected_if":["patched-version"],"how_to_check":"Check the installed Firefox or Thunderbird version under Help/About and compare it with the fixed release in the vendor advisory; the sources do not name the fixed version.","fix":"Update Firefox and Thunderbird to the latest release per vendor instructions, as CISA requires.","status":"open","published_at":"2019-07-23T14:15:15+00:00","first_seen_at":"2026-10-23T19:11:52+00:00","triaged_at":"2026-10-23T21:16:08+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-23T21:16:08Z","model":"claude-haiku-5-5","output":{"fix":"Update Firefox and Thunderbird to the latest release per vendor instructions, as CISA requires.\nunknown","reach":"internet","impact":"high","summary":"Mozilla Firefox and Thunderbird have a type confusion bug in the JavaScript Array.pop handling, reachable by manipulating JavaScript objects. An attacker who lures a user to a crafted page can cause a crash and, per the CISA listing, the flaw is known to be exploited in the wild.","category":"package","who_cares":["firefox","thunderbird","desktop","browser"],"confidence":0.6,"needs_auth":"no","worst_case":"Browser process crashes, with exploitation possible for code execution in the browser","analyst_note":"Find the Mozilla advisory (MFSA 2019-18 or similar) for the fixed Firefox and Thunderbird versions and confirm the code execution claim.","how_to_check":"Check the installed Firefox or Thunderbird version under Help/About and compare it with the fixed release in the vendor advisory; the sources do not name the fixed version.\nunknown\nunknown","needs_analyst":true,"not_affected_if":["patched-version"],"user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000505,"input_tokens":2867,"output_tokens":437,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-11707':14A,17A '-2019':13A,16A '60.7.1':115C '60.7.2':120C '67.0.3':117C 'abus':107C 'affect':112C 'allow':93C 'and':20A 'array.pop':40B,90C 'attack':48B,103C 'awar':100C 'browser':22B 'bug':36B 'caus':58B 'cisa':64B 'confus':10A,35B,78C 'craft':55B 'crash':60B,97C 'cve':12A,15A 'desktop':23B 'due':86C 'esr':114C 'exploit':24B,72B,96C 'firefox':2A,6A,19A,25B,29B,113C,116C 'flaw':67B,109C 'handl':41B 'issu':88C 'javascript':39B,45B,84C 'known':69B 'list':65B 'lure':50B 'manipul':44B,83C 'mozilla':1A,5A,18A,28B 'object':46B,85C 'occur':81C 'packag':26B 'page':56B 'per':62B 'reachabl':42B 'target':102C 'thunderbird':4A,8A,21A,27B,31B,119C 'type':9A,34B,77C 'user':52B 'vulner':11A,79C,111C 'wild':75B,106C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2019-07-23T14:15:15+00:00","kev":{"dateAdded":"2022-05-23","dueDate":"2022-06-13","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2019-11707","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2019-11707","severity":null,"published_at":"2022-05-23T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:52+00:00","fetched_at":"2026-10-25T11:39:16+00:00","note":null},{"source":"epss","external_id":"CVE-2019-11707","url":"https://api.first.org/data/v1/epss?cve=CVE-2019-11707","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:45+00:00","fetched_at":"2026-10-23T19:13:45+00:00","note":null},{"source":"nvd","external_id":"CVE-2019-11707","url":"https://nvd.nist.gov/vuln/detail/CVE-2019-11707","severity":null,"published_at":"2019-07-23T14:15:15+00:00","modified_at":"2026-06-17T02:13:28+00:00","first_seen_at":"2026-10-23T21:57:35+00:00","fetched_at":"2026-10-23T21:57:35+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"}