CVE-2018-5124 — firefox: Unsanitized output in browser UI can lead to arbitrary code execution

MEDIUM

firefox: Unsanitized output in browser UI can lead to arbitrary code execution

Published Apr 26, 2019

6.1

MEDIUM

CVSS 3.0

EPSS 1.01%

Unsanitized output in the browser UI leaves HTML tags in place and can result in arbitrary code execution in Firefox before version 58.0.1.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor

Product

Default status

Versions

n/a

Firefox

n/a

Version	Status	Constraints
All versions prior to Firefox 58.0.1	affected	-

Product	Package	State	Advisory
Red Hat Enterprise Linux 5	firefox	Not affected	n/a
Red Hat Enterprise Linux 6	firefox	Not affected	n/a
Red Hat Enterprise Linux 7	firefox	Not affected	n/a

No remediation recorded yet.

1.01% 0.01013

Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.

EPSS probability 0.01013

2021–2026

Table of values (9 key points)

Flat stretches are collapsed; showing up to 120 newest points.

Date	Score	Percentile	Model
Oct 1, 2026	1.01% (0.01013)	61.92th	v5 (v2026.06.15)
Sep 20, 2026	1.01% (0.01013)	61.72th	v5 (v2026.06.15)
Jul 20, 2024	0.09% (0.00089)	38.41th	v3 (v2023.03.01)
Sep 3, 2023	0.09% (0.00089)	36.83th	v3 (v2023.03.01)
Mar 7, 2023	0.07% (0.00069)	28.02th	v3 (v2023.03.01)
Mar 6, 2023	1.09% (0.01086)	53.47th	v2 (v2022.01.01)
Feb 4, 2022	1.09% (0.01086)	28.42th	v2 (v2022.01.01)
Feb 3, 2022	0.78% (0.00776)	21.05th	v5 (v2026.06.15)
Apr 14, 2021	0.78% (0.00776)	0.00th	v1

Weaknesses (1)

CWE-79

Cross-site Scripting (XSS)

Link	Providers	Tags
https://access.redhat.com/security/cve/CVE-2018-5124		Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1540431		Issue Tracking
https://nvd.nist.gov/vuln/detail/CVE-2018-5124
https://www.cve.org/CVERecord?id=CVE-2018-5124
https://www.mozilla.org/en-US/security/advisories/mfsa2018-05/		x_refsource_MISCVendor Advisory