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Public proof of conceptFix available

CVE-2019-9792

A public proof of concept exists; no exploitation attested.

  • Published2019-04-26
  • WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The IonMonkey just-in-time (JIT) compiler can leak an internal JS_OPTIMIZED_OUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

Timeline

dates in UTC
  1. 2019-05-29Exploit-DB entryExploit-DB

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-9792?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-9792?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Redhat enterprise linux eus
BranchAffectedFixed in
8.1= 8.1no fix published
8.2= 8.2no fix published
8.4= 8.4no fix published
Mozilla firefox
BranchAffectedFixed in
66.0< 66.066.0
60.6< 60.6.060.6.0
Redhat enterprise linux server aus
BranchAffectedFixed in
8.2= 8.2no fix published
8.4= 8.4no fix published

3 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • firefoxUbuntu:18.04:LTSall versions · fixed in 66.0+build3-0ubuntu0.18.04.1
  • firefoxUbuntu:16.04:LTSall versions · fixed in 66.0+build3-0ubuntu0.16.04.2
  • firefoxUbuntu:14.04:LTSall versions · fixed in 66.0.1+build1-0ubuntu0.14.04.1
  • firefoxRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:60.6.1-1.el8and 5 other packages
  • firefoxRed Hat:enterprise_linux:7::workstationall versions · fixed in 0:60.6.0-3.el7_6and 1 other package
  • firefoxRed Hat:enterprise_linux:7::serverall versions · fixed in 0:60.6.0-3.el7_6and 1 other package
  • firefoxRed Hat:enterprise_linux:7::clientall versions · fixed in 0:60.6.0-3.el7_6and 1 other package
  • firefoxRed Hat:enterprise_linux:6::workstationall versions · fixed in 0:60.6.0-3.el6_10and 1 other package

69 more package ranges on OSV.dev

Vendor advisories

  • CVE-2019-9792 Red Hat Product Security113 products fixed

    Mozilla: IonMonkey leaks JS_OPTIMIZED_OUT magic value to script

  • RHSA-2019:1144 Red Hat Product Security7 products fixed

    Red Hat Security Advisory: thunderbird security update

  • RHSA-2019:0966 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: firefox security update

  • RHSA-2019:0681 Red Hat Product Security16 products fixed

    Red Hat Security Advisory: thunderbird security update

  • RHSA-2019:0680 Red Hat Product Security19 products fixed

    Red Hat Security Advisory: thunderbird security update

  • RHSA-2019:0623 Red Hat Product Security30 products fixed

    Red Hat Security Advisory: firefox security update

1 more advisory

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2019:1144 · 7 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 All running instances of Thunderbird must be restarted for the update to take effect.
  2. Vendor fix Red Hat Product Security RHSA-2019:0966 · 13 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 After installing the update, Firefox must be restarted for the changes to take effect.

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-46939
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.19.8read 2026-10-23
  • NVDCVSS 2.07.5read 2026-10-23
  • NVDweakness (CWE)CWE-787read 2026-10-23
  • FIRST EPSSEPSS score13.3 %read 2026-11-03
  • Exploit-DBdetectionread 2026-11-03
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2019-04-26
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2019-9792?

The IonMonkey just-in-time (JIT) compiler can leak an internal JS_OPTIMIZED_OUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

Is CVE-2019-9792 actively exploited?

Active exploitation of CVE-2019-9792 has not been confirmed. Its EPSS score was 13.3% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-9792?

CVE-2019-9792 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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