Vulnerability in Mozilla Firefox

CVE-2019-9813

Incorrect handling of __proto__ mutations may lead to type confusion in IonMonkey JIT code and can be leveraged for arbitrary memory read and write. This vulnerability affects Firefox < 66.0.1, Firefox ESR < 60.6.1, and Thunderbird < 60.6.1.

EPSS: 0.074 (93.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2019-9813?
CVE-2019-9813 is a high-severity vulnerability in Mozilla Firefox, classified under Access of Resource Using Incompatible Type (Type Confusion). CVSS score: 8.8/10. Published 2019-04-26.
How severe is CVE-2019-9813?
High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2019-9813 known to be exploited?
12 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.