{"id":"CVE-2019-17026","url":"https://www.cyber-defence.io/tools/cve/CVE-2019-17026","generatedAt":"2026-10-27T21:18:54.151Z","title":"Mozilla Firefox And Thunderbird Type Confusion Vulnerability","description":"Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.","published":"2020-03-02T05:15:12.000Z","lastModified":"2026-06-17T02:23:11.000Z","status":"Analyzed","sourceIdentifier":"security@mozilla.org","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},"cwe":["CWE-843"],"affected":["mozilla/firefox","mozilla/thunderbird","canonical/ubuntu linux"],"epss":{"score":0.46311,"percentile":0.98809,"date":"2026-10-26","history":[]},"kev":{"listed":true,"dateAdded":"2021-11-03","dueDate":"2022-05-03","knownRansomwareCampaignUse":"Unknown","notes":"Apply updates per vendor instructions.\nhttps://nvd.nist.gov/vuln/detail/CVE-2019-17026"},"exploits":{"count":1,"verified":false,"firstPublished":"2021-05-13","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":49864,"kind":"exploit","title":"Firefox 72 IonMonkey - JIT Type Confusion","url":"https://www.exploit-db.com/exploits/49864","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/windows_x86-64/local/49864.js","file":"exploits/windows_x86-64/local/49864.js","published":"2021-05-13","added":"2021-05-13","updated":"2021-05-13","author":"Forrest Orr","type":"local","platform":"windows_x86-64","port":null,"verified":false,"codes":["CVE-2019-17026"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":null}]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 3 May 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"security@mozilla.org"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1607443","tags":["Issue Tracking"],"source":"security@mozilla.org"},{"url":"https://security.gentoo.org/glsa/202003-02","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://usn.ubuntu.com/4335-1/","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2020-03/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2020-04/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1607443","tags":["Issue Tracking"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202003-02","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4335-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2020-03/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2020-04/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-17026","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2019-17026","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}