CVE-2019-9792

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
9.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • Public exploit code is available (Exploit-DB (verified), epss top5pct, public exploit)
CISA-KEV: Not listedEPSS PROB: 13%CVSS: 9.8Exploit: Exploit-DB (verified) · epss top5pct · public exploitExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
75(Track*)
EG Risk 75/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation65% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
13%
EPSS %ILE
96%
KEV
Not listed

Published

April 26, 2019

Last Modified

November 25, 2025

Advisory Details (7)

Auto-updated Aug 20, 2026
Patch available. Sources: redhat.
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2019:1144
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2019:0966
generic

Locked Out | Packet Storm

http://packetstormsecurity.com/files/153106/Spidermonkey-IonMonkey-JS_OPTIMIZED_OUT-Value-Leak.html
generic

Security vulnerabilities fixed in Thunderbird 60.6 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-11/
generic

Security vulnerabilities fixed in Firefox ESR 60.6 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-08/
generic

Security vulnerabilities fixed in Firefox 66 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-07/
generic

1532599 - (CVE-2019-9792) Spidermonkey: IonMonkey leaks JS_OPTIMIZED_OUT magic value to script

https://bugzilla.mozilla.org/show_bug.cgi?id=1532599

Vendor Advisories for CVE-2019-9792(6)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(9)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntufirefox-testsuite (66.0+build3-0ubuntu0.18.10.1) @ cosmic2026-05-27ubuntu
ubuntuxul-ext-lightning (1:60.6.1+build2-0ubuntu0.16.04.1) @ xenial2026-05-27ubuntu
ubuntufirefox-testsuite (66.0.1+build1-0ubuntu0.14.04.1) @ trusty2026-05-27ubuntu
redhatthunderbird-0:60.6.1-1.el82019-05-13redhat
redhatfirefox-0:60.6.1-1.el82019-05-07redhat
redhatthunderbird-0:60.6.1-1.el6_102019-03-28redhat
redhatthunderbird-0:60.6.1-1.el7_62019-03-28redhat
redhatfirefox-0:60.6.0-3.el6_102019-03-20redhat
redhatfirefox-0:60.6.0-3.el7_62019-03-20redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(12 across 6 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—60.6.0esr-1—
thunderbird—1:60.6.1-1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—60.6.0esr-1—
thunderbird—1:60.6.1-1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—60.6.0esr-1—
thunderbird—1:60.6.1-1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—60.6.0esr-1—
thunderbird—1:60.6.1-1—
Debian:8(2)
PackageVulnerable rangeFixed inDependents
firefox-esr45.0.1esr-1 ... 60.5.1esr-1~deb9u1 (128 versions)60.6.0esr-1~deb8u1—
thunderbird1.5-4 ... 1:60.5.1-1~deb9u1 (71 versions)1:60.6.1-1~deb8u1—
Debian:9(2)
PackageVulnerable rangeFixed inDependents
firefox-esr45.9.0esr-1 ... 60.6.0esr-1~deb8u1 (91 versions)60.6.0esr-1~deb9u1—
thunderbird1.5-4 ... 1:60.6.1-1~deb8u1 (72 versions)1:60.6.1-1~deb9u1—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(3)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 6× in last 7d / 24× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 111 total refreshes for this CVE.

  1. 2026-08-20 22:51 UTCEPSS rescore
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Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-46939✓ verified
    First seen May 29, 2019

    Spidermonkey - IonMonkey Leaks JS_OPTIMIZED_OUT Magic Value to Script

    Open source ↗

Frequently asked(5)

What is CVE-2019-9792?
CVE-2019-9792 is a critical vulnerability published on April 26, 2019. The IonMonkey just-in-time (JIT) compiler can leak an internal JSOPTIMIZEDOUT 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 <…
When was CVE-2019-9792 disclosed?
CVE-2019-9792 was first published in the National Vulnerability Database on April 26, 2019, with the most recent update on November 25, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2019-9792 actively exploited?
CVE-2019-9792 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 13% probability of exploitation in the next 30 days, which ranks it in the top 3.9% of all scored CVEs.
What is the CVSS score of CVE-2019-9792?
CVE-2019-9792 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2019-9792?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-9792, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2019-9792

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