How severe is CVE-2019-11707?

CVE-2019-11707 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-11707 being actively exploited?

Yes. CVE-2019-11707 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-05-23, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2019-11707?

CVE-2019-11707 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-11707?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2019-11707 have an EU (EUVD) identifier?

Yes. CVE-2019-11707 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2019-3377. It is also flagged as exploited in the EUVD (since 2022-05-23).

When was CVE-2019-11707 published?

CVE-2019-11707 was published on 2019-07-23 and last updated on 2026-06-17.

CVE-2019-11707

CVE-2019-11707 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-05-23). The underlying weakness is classified as CWE-843.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 7.5
EPSS exploit prediction: 38% (98th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-05-23)
EU (EUVD) id: EUVD-2019-3377
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-05-23)
Weakness: CWE-843
Affected product: Mozilla Firefox
Published: 2019-07-23
Last modified: 2026-06-17

Description

A type confusion vulnerability can occur when manipulating JavaScript objects due to issues in Array.pop. This can allow for an exploitable crash. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 60.7.1, Firefox < 67.0.3, and Thunderbird < 60.7.2.

Frequently asked questions

What is CVE-2019-11707?: A type confusion vulnerability can occur when manipulating JavaScript objects due to issues in Array.pop. This can allow for an exploitable crash. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 60.7.1, Firefox < 67.0.3, and Thunderbird < 60.7.2.
How severe is CVE-2019-11707?: CVE-2019-11707 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-11707 being actively exploited?: Yes. CVE-2019-11707 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-05-23, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2019-11707?: CVE-2019-11707 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-11707?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2019-11707 have an EU (EUVD) identifier?: Yes. CVE-2019-11707 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2019-3377. It is also flagged as exploited in the EUVD (since 2022-05-23).
When was CVE-2019-11707 published?: CVE-2019-11707 was published on 2019-07-23 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

More vulnerabilities in Mozilla Firefox

CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4692 — Critical (CVSS 10.0): Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR…
CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…

All CVEs affecting Mozilla Firefox →

Other CWE-843 vulnerabilities

CVE-2021-33970 — Critical (CVSS 10.0): Buffer Overflow vulnerability in Qihoo 360 Chrome v13.0.2170.0 allows attacker to escalate priveleges.
CVE-2010-2299 — Critical (CVSS 10.0): The Clipboard::DispatchObject function in app/clipboard/clipboard.cc in Google Chrome before 5.0.375.70 does not…
CVE-2023-22579 — Critical (CVSS 9.9): Due to improper parameter filtering in the sequalize js library, can a attacker peform injection.
CVE-2026-13776 — Critical (CVSS 9.8): Type Confusion in Dawn in Google Chrome prior to 150.0.7871.47 allowed a remote attacker who had compromised the…
CVE-2026-43038 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: ipv6: icmp: clear skb2->cb[] in…
CVE-2025-70023 — Critical (CVSS 9.8): An issue pertaining to CWE-843: Access of Resource Using Incompatible Type was discovered in transloadit uppy v0.25.6.

Browse all CWE-843 vulnerabilities →