Use After Free in Mozilla Firefox

CVE-2017-5447

An out-of-bounds read during the processing of glyph widths during text layout. This results in a potentially exploitable crash and could allow an attacker to read otherwise inaccessible memory. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

Vulnerability class: Use-After-Free

EPSS: 0.175 (96.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2017-5447?
CVE-2017-5447 is a critical-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 9.1/10. Published 2018-06-11.
How severe is CVE-2017-5447?
Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2017-5447 known to be exploited?
8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.