← Vulnerability feed

Vulnerability record · CVE-2019-9791 · published 26 April 2019

CVE-2019-9791: Mozilla firefox type confusion vulnerability

Mozilla · Firefox

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.

9.8 CVSS 3.1 Critical EPSS 20% · top 2.7% CWE-843 · Type confusion
9.8CVSS 3.1 base score, v2 7.5
20%EPSS exploitation probability, 30 days
NoNot in CISA KEV
6Affected product versions listed by NVD
12References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

6 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2019:0966 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:1144 Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1530958 ExploitIssue TrackingVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/ Vendor Advisory
https://access.redhat.com/errata/RHSA-2019:0966 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:1144 Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1530958 ExploitIssue TrackingVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/ Vendor Advisory

Track CVE-2019-9791 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2019-11708Mozilla Firefox and Thunderbird sandbox escape via Prompt:Open IPC validation flawThe Prompt:Open IPC message between child and parent processes does not sufficiently vet its parameters, letting a compromised child process cause th…KEVEPSS 56%analysed9.8CVE-2024-9680Mozilla Firefox and Thunderbird use-after-free in Animation timelinesA use-after-free flaw in Animation timelines allows an attacker to execute code in the content process of Firefox and Thunderbird. Mozilla reports ex…KEVEPSS 23%analysed9.8CVE-2019-5544OpenSLP heap out-of-bounds write in VMware ESXi and Horizon DaaSOpenSLP as shipped in VMware ESXi and Horizon DaaS contains a heap overwrite (out-of-bounds write) flaw. VMware rates it Critical with a maximum CVSS…KEVEPSS 97%analysed9.8CVE-2019-11043PHP-FPM buffer overflow enables remote code executionPHP-FPM in certain configurations writes past allocated buffers into FCGI protocol data space, an out-of-bounds write (CWE-787, CWE-120). It affects …KEVEPSS 100%analysed9.8CVE-2018-14667RichFaces Framework EL injection enables unauthenticated remote code executionRichFaces Framework 3.X through 3.3.4 is vulnerable to Expression Language injection through the UserResource resource. A remote, unauthenticated att…KEVEPSS 74%analysed9.8CVE-2016-3427Oracle Java SE JMX Improper Access Control VulnerabilityCVE-2016-3427 is an unspecified vulnerability in Oracle Java SE 6u113, 7u99, 8u77, Java SE Embedded 8u77, and JRockit R28.3.9, reached through vector…KEVEPSS 92%analysed9.8CVE-2015-2590Oracle Java SE Libraries flaw allows remote code executionCVE-2015-2590 is an unspecified vulnerability in the Libraries component of Oracle Java SE 6u95, 7u80, 8u45 and Java SE Embedded 7u75, 8u33. The reco…KEVEPSS 25%analysed9.8CVE-2015-5119Adobe Flash Player ActionScript 3 ByteArray use-after-freeA use-after-free flaw exists in the ByteArray class of the ActionScript 3 implementation in Adobe Flash Player. Crafted Flash content that overrides …KEVEPSS 99%analysed

Source: NIST National Vulnerability Database (record CVE-2019-9791), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.