Threats / Mozilla / CVE-2019-11707
CVE-2019-11707
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Mozilla Firefox and Thunderbird vulnerability
Mozilla Firefox and Thunderbird contain a type confusion vulnerability in Array.pop that allows remote code execution through malicious JavaScript, exploited in the wild.
Verdict
Today item — known-exploited.
A type confusion flaw in JavaScript object handling enables attackers to achieve code execution via crafted web content or email attachments. The vulnerability is actively exploited and carries high severity despite no CVSS score assignment.
CISA KEV Yes · 2022-05-234EPSS 0.37951 (verify live)5Exploit Weaponized · public PoC6CVSS 8.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-23).
Probability (EPSS)
EPSS 0.37951 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) · Affected: Mozilla, Firefox and Thunderbird. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-843 Type Confusion — weakness family: Memory safety.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 1035 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft malicious JavaScript that exploits type confusion in Array.pop to corrupt memory and bypass security checks.
Business
Users visiting compromised websites or opening malicious email attachments face arbitrary code execution on their systems.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I trigger the vulnerability through a web page or email message that the victim's browser or email client automatically processes.
Business
Attackers gain execution context within the browser or email application, potentially compromising user data and system integrity.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05