VulnTideExploited vulnerabilities, by vendor. Data as of .
Known exploitedIn CISA's KEV catalog since Ransomware use: unknown
Mozilla Firefox and Thunderbird

CVE-2019-11707: Mozilla Firefox and Thunderbird Type Confusion Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 1,035 days after the CVE record was published.

How likely is exploitation in the next 30 days?
38%

EPSS score, percentile 98.5 of all scored records

How severe?
8.8 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA deadline . Apply updates per vendor instructions.

Advisories and patches (1)

Which versions are affected?

Affected

  • before 60.7.1
  • before 67.0.3
  • before 60.7.2

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

What to do

Required action, set by CISA

Apply updates per vendor instructions.

CISA due date for this action: .

Advisories and patches

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Mozilla Firefox ESR
StatusVersions
Affectedbefore 60.7.1
Mozilla Firefox
StatusVersions
Affectedbefore 67.0.3
Mozilla Thunderbird
StatusVersions
Affectedbefore 60.7.2

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

About this vulnerability

Mozilla Firefox and Thunderbird contain a type confusion vulnerability that can occur when manipulating JavaScript objects due to issues in Array.pop, allowing for an exploitable crash.

Summary: CISA's KEV catalog, as of .

  • CISA added CVE-2019-11707 to its Known Exploited Vulnerabilities (KEV) catalog on 23 May 2022.
  • CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
  • The due date CISA sets for the required action is 13 Jun 2022.
  • The CVE record was published on 23 Jul 2019, 1,035 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 8.8 (High), taken from CISA's enrichment of the record.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 38% (percentile 98.5), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

Weakness

  • CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
CVE record published
Added to CISA KEV
CISA due date for the required action
CVE record last updated

References

More exploited Mozilla vulnerabilities

  • CVE-2010-3765: Mozilla Multiple Products Remote Code Execution Vulnerability (added )
  • CVE-2024-9680: Mozilla Firefox Use-After-Free Vulnerability (added )
  • CVE-2016-9079: Mozilla Firefox, Firefox ESR, and Thunderbird Use-After-Free Vulnerability (added )
  • CVE-2015-4495: Mozilla Firefox Security Feature Bypass Vulnerability (added )
  • CVE-2019-11708: Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability (added )
  • CVE-2013-1690: Mozilla Firefox and Thunderbird Denial-of-Service Vulnerability (added )