What is CVE-2019-11708?

CVE-2019-11708 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Input Validation. CVSS score: 10.0/10. Published 2019-07-23.

How severe is CVE-2019-11708?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Is CVE-2019-11708 known to be exploited?

Yes. CVE-2019-11708 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-23), indicating it is being actively exploited. 53 public proof-of-concept repositories are indexed.

Improper input validation in Mozilla Firefox

CVE-2019-11708

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.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2019-07-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.559 (99.0th percentile), scored 2026-10-18.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.559 · newest: 0.559 · change: 0.000

Affected products

Mozilla Firefox — versions unspecified
Mozilla Firefox Esr — versions unspecified
Mozilla Thunderbird — versions unspecified

Weakness classification (CWE)

CWE-20 — Improper Input Validation

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2022-05-23. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-06-13.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

www.mozilla.org/security/advisories/mfsa2019-19/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2019-20/ (Vendor Advisory)
bugzilla.mozilla.org/show_bug.cgi (Issue Tracking, Vendor Advisory)
security.gentoo.org/glsa/201908-12 (vendor-advisory, Third Party Advisory)
packetstormsecurity.com/files/155592/Mozilla-Firefox-Windows-64-Bit-Chain-Explo… (VDB Entry, Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2019-11708?: CVE-2019-11708 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Input Validation. CVSS score: 10.0/10. Published 2019-07-23.
How severe is CVE-2019-11708?: Critical severity. CVSS v3 base score is 10.0 out of 10.
Is CVE-2019-11708 known to be exploited?: Yes. CVE-2019-11708 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-23), indicating it is being actively exploited. 53 public proof-of-concept repositories are indexed.