What is CVE-2018-18503?

CVE-2018-18503 is a high-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 8.8/10. Published 2019-02-05.

How severe is CVE-2018-18503?

High severity. CVSS v3 base score is 8.8 out of 10.

Buffer overflow in Mozilla Firefox

CVE-2018-18503

When JavaScript is used to create and manipulate an audio buffer, a potentially exploitable crash may occur because of a compartment mismatch in some situations. This vulnerability affects Firefox < 65.

Vulnerability class: Buffer Overflow

Published 2019-02-05 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.014 (71.0th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Mozilla Firefox — versions unspecified
Canonical Ubuntu Linux — versions 14.04, 16.04, 18.04

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

www.mozilla.org/security/advisories/mfsa2019-01/ (Vendor Advisory)
www.securityfocus.com/bid/106773 (VDB Entry, Third Party Advisory, vdb-entry)
usn.ubuntu.com/3874-1/ (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2018-18503?: CVE-2018-18503 is a high-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 8.8/10. Published 2019-02-05.
How severe is CVE-2018-18503?: High severity. CVSS v3 base score is 8.8 out of 10.