{"id":"CVE-2019-9791","url":"https://www.cyber-defence.io/tools/cve/CVE-2019-9791","generatedAt":"2026-10-27T20:19:58.383Z","title":"The type inference system allows the compilation of functions that can cause type confusions between arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor function is entered through on-stack…","description":"The type inference system allows the compilation of functions that can cause type confusions between arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor function is entered through on-stack replacement (OSR). This allows for possible arbitrary reading and writing of objects during an exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.","published":"2019-04-26T17:29:02.000Z","lastModified":"2026-06-17T02:44:21.000Z","status":"Modified","sourceIdentifier":"security@mozilla.org","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-843"],"affected":["mozilla/firefox","mozilla/thunderbird","redhat/enterprise linux","redhat/enterprise linux eus","redhat/enterprise linux server aus","redhat/enterprise linux server tus"],"epss":{"score":0.19915,"percentile":0.97408,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":1,"verified":true,"firstPublished":"2019-03-26","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":46613,"kind":"exploit","title":"Spidermonkey - IonMonkey Type Inference is Incorrect for Constructors Entered via OSR","url":"https://www.exploit-db.com/exploits/46613","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/multiple/dos/46613.js","file":"exploits/multiple/dos/46613.js","published":"2019-03-26","added":"2019-03-26","updated":"2019-03-26","author":"Google Security Research","type":"dos","platform":"multiple","port":null,"verified":true,"codes":["CVE-2019-9791"],"tags":"Type Confusion","aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":"https://bugs.chromium.org/p/project-zero/issues/detail?id=1791"}]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 19.9%, higher than 97% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"https://access.redhat.com/errata/RHSA-2019:0966","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:1144","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1530958","tags":["Exploit","Issue Tracking","Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-07/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-08/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-11/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:0966","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:1144","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1530958","tags":["Exploit","Issue Tracking","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-07/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-08/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-11/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2019-9791","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."}