CVE-2019-11708: Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 23 May 2022, 1,035 days after the CVE record was published.

How likely is exploitation in the next 30 days?

55.9%

EPSS score, percentile 99 of all scored records

How severe?

10.0 Critical

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

What should I do?

Required action (CISA), due 13 Jun 2022: Apply updates per vendor instructions.

Advisories and patches (1)

Which versions are affected?

Affected: before 60.7.2; before 67.0.4; before 60.7.2

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 13 June 2022.

Advisories and patches

• GLSA-201908-12 (Vendor advisory)

Linked from CISA's catalog entry

• https://nvd.nist.gov/vuln/detail/CVE-2019-11708

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Mozilla Firefox and Thunderbird contain a sandbox escape vulnerability that could result in remote code execution.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2019-11708 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 10.0 (Critical), taken from CISA's enrichment of the record.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 55.9% (percentile 99), 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 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxed parent process opening web content chosen by a compromised child process. When combined with additional vulnerabilities this could result in executing arbitrary code on the user's computer. This vulnerability affects Firefox ESR < 60.7.2, Firefox < 67.0.4, and Thunderbird < 60.7.2.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-20: Improper Input Validation

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

Timeline

References

• mozilla.org
• mozilla.org
• bugzilla.mozilla.org
• packetstormsecurity.com

More exploited Mozilla vulnerabilities

• CVE-2010-3765: Mozilla Multiple Products Remote Code Execution Vulnerability (added 6 Oct 2025)
• CVE-2024-9680: Mozilla Firefox Use-After-Free Vulnerability (added 15 Oct 2024)
• CVE-2016-9079: Mozilla Firefox, Firefox ESR, and Thunderbird Use-After-Free Vulnerability (added 22 Jun 2023)
• CVE-2015-4495: Mozilla Firefox Security Feature Bypass Vulnerability (added 25 May 2022)
• CVE-2019-11707: Mozilla Firefox and Thunderbird Type Confusion Vulnerability (added 23 May 2022)
• CVE-2013-1690: Mozilla Firefox and Thunderbird Denial-of-Service Vulnerability (added 28 Mar 2022)