CVE-2019-9819

CRITICALNVD 9.89.8—

9.8

A vulnerability where a JavaScript compartment mismatch can occur while working with the fetch API, resulting 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)
EPSS: 74.1%
KEV: Not listed

Published

July 23, 2019

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated May 27, 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

1532553 - (CVE-2019-9819) Compartment mismatch in APIUnwrapAndDowncast<js::ReadableStream>

https://bugzilla.mozilla.org/show_bug.cgi?id=1532553

Patch Availability(8)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	xul-ext-lightning (1:60.7.0+build1-0ubuntu0.16.04.1) @ xenial	2026-05-27	ubuntu
ubuntu	firefox-testsuite (67.0+build2-0ubuntu0.16.04.1) @ xenial	2026-05-27	ubuntu
redhat	thunderbird-0:60.7.0-1.el7_6	2019-06-03	redhat
redhat	thunderbird-0:60.7.0-1.el6_10	2019-06-03	redhat
redhat	thunderbird-0:60.7.0-1.el8_0	2019-06-03	redhat
redhat	firefox-0:60.7.0-1.el6_10	2019-05-23	redhat
redhat	firefox-0:60.7.0-1.el7_6	2019-05-23	redhat
redhat	firefox-0:60.7.0-1.el8_0	2019-05-23	redhat

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.

Weakness Classification(2)

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 11× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:14 UTCepss_batch
2026-05-31 00:14 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 17:03 UTCEG score recompute
2026-05-27 17:03 UTCVendor advisory
2026-05-27 17:03 UTCGHSA enrichment
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:38 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2019-9819?

CVE-2019-9819 is a critical vulnerability published on July 23, 2019. A vulnerability where a JavaScript compartment mismatch can occur while working with the fetch API, resulting in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.

When was CVE-2019-9819 disclosed?

CVE-2019-9819 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-2019-9819 actively exploited?

CVE-2019-9819 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 74.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2019-9819?

CVE-2019-9819 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2019-9819?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-9819, 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-2019-9819

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CVE-2019-9819

Published

Last Modified

Advisory Details (4)

Security vulnerabilities fixed in Thunderbird 60.7 — Mozilla

Security vulnerabilities fixed in Firefox ESR 60.7 — Mozilla

Security vulnerabilities fixed in Firefox 67 — Mozilla

1532553 - (CVE-2019-9819) Compartment mismatch in APIUnwrapAndDowncast<js::ReadableStream>

Patch Availability(8)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2019-9819?

Same vendor

Same CWE

CVE-2019-9819

📅 Published

🔄 Last Modified

📋 Advisory Details (4)

Security vulnerabilities fixed in Thunderbird 60.7 — Mozilla

Security vulnerabilities fixed in Firefox ESR 60.7 — Mozilla

Security vulnerabilities fixed in Firefox 67 — Mozilla

1532553 - (CVE-2019-9819) Compartment mismatch in APIUnwrapAndDowncast<js::ReadableStream>

Patch Availability(8)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2019-9819?

🔗 Related CVEs(same vendor + same CWE)

Same vendor

Same CWE

Published

Last Modified

Advisory Details (4)

Frequently asked(5)

Related CVEs(same vendor + same CWE)