CVE-2019-9820

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
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

A use-after-free vulnerability can occur in the chrome event handler when it is freed while still in use. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
74%
KEV
Not listed

Published

July 23, 2019

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Aug 16, 2026
No patch confirmed yet.
generic

Security vulnerabilities fixed in Thunderbird 60.7 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-15/
generic

Security vulnerabilities fixed in Firefox ESR 60.7 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-14/
generic

Security vulnerabilities fixed in Firefox 67 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-13/
generic

1536405 - (CVE-2019-9820) heap-use-after-free in nsDocShell::GetChromeEventHandler

https://bugzilla.mozilla.org/show_bug.cgi?id=1536405

Patch Availability(8)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuxul-ext-lightning (1:60.7.0+build1-0ubuntu0.16.04.1) @ xenial2026-05-27ubuntu
ubuntufirefox-testsuite (67.0+build2-0ubuntu0.16.04.1) @ xenial2026-05-27ubuntu
redhatthunderbird-0:60.7.0-1.el7_62019-06-03redhat
redhatthunderbird-0:60.7.0-1.el6_102019-06-03redhat
redhatthunderbird-0:60.7.0-1.el8_02019-06-03redhat
redhatfirefox-0:60.7.0-1.el6_102019-05-23redhat
redhatfirefox-0:60.7.0-1.el7_62019-05-23redhat
redhatfirefox-0:60.7.0-1.el8_02019-05-23redhat

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—60.7.0esr-1—
thunderbird—1:60.7.0-1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—60.7.0esr-1—
thunderbird—1:60.7.0-1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—60.7.0esr-1—
thunderbird—1:60.7.0-1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—60.7.0esr-1—
thunderbird—1:60.7.0-1—
Debian:8(2)
PackageVulnerable rangeFixed inDependents
firefox-esr45.0.1esr-1 ... 60.6.3esr-1~deb9u1 (139 versions)60.7.0esr-1~deb8u1—
thunderbird1.5-4 ... 1:60.6.1-1~deb9u1 (74 versions)1:60.7.0-1~deb8u1—
Debian:9(2)
PackageVulnerable rangeFixed inDependents
firefox-esr45.9.0esr-1 ... 60.7.0esr-1~deb8u1 (102 versions)60.7.0esr-1~deb9u1—
thunderbird1.5-4 ... 1:60.7.0-1~deb8u1 (75 versions)1:60.7.0-1~deb9u1—

Weakness Classification(1)

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

All Vendor Advisories

(8)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 31× 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 127 total refreshes for this CVE.

  1. 2026-08-21 18:14 UTCOSV refresh
  2. 2026-08-20 22:51 UTCEPSS rescore
  3. 2026-08-19 17:00 UTCEPSS rescore
  4. 2026-08-18 13:44 UTCEPSS rescore
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  14. 2026-08-06 13:43 UTCEPSS rescore
  15. 2026-08-06 02:51 UTCOSV refresh
  16. 2026-08-05 19:14 UTCEPSS rescore
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  1. 2026-07-25 14:14 UTCEPSS rescore
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  5. 2026-07-23 01:47 UTCEG score recompute
  6. 2026-07-22 22:30 UTCEG score recompute
  7. 2026-07-22 14:05 UTCEPSS rescore
  8. 2026-07-21 15:22 UTCEPSS rescore
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  10. 2026-07-20 17:04 UTCEPSS rescore
  11. 2026-07-20 12:32 UTCOSV refresh
  12. 2026-07-19 14:28 UTCEPSS rescore
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  20. 2026-07-13 22:27 UTCEPSS rescore
  21. 2026-07-12 05:44 UTCEPSS rescore
  22. 2026-07-11 08:24 UTCEPSS rescore
  23. 2026-07-09 19:06 UTCEPSS rescore
  24. 2026-07-08 15:11 UTCEPSS rescore
  25. 2026-07-07 13:43 UTCEPSS rescore
  26. 2026-07-06 16:25 UTCEPSS rescore
  27. 2026-07-06 16:25 UTCEPSS rescore
  28. 2026-07-06 02:20 UTCEPSS rescore
  29. 2026-07-05 02:27 UTCEPSS rescore
  30. 2026-07-04 06:28 UTCEPSS rescore
  31. 2026-07-03 07:26 UTCOSV refresh
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  63. 2026-06-14 22:13 UTCOSV refresh
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Frequently asked(5)

What is CVE-2019-9820?
CVE-2019-9820 is a critical vulnerability published on July 23, 2019. A use-after-free vulnerability can occur in the chrome event handler when it is freed while still in use. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.
When was CVE-2019-9820 disclosed?
CVE-2019-9820 was first published in the National Vulnerability Database on July 23, 2019, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2019-9820 actively exploited?
CVE-2019-9820 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 25.5% of all scored CVEs.
What is the CVSS score of CVE-2019-9820?
CVE-2019-9820 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2019-9820?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-9820, 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-2019-9820

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