SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-5101

A use-after-free vulnerability can occur when manipulating floating "first-letter" style elements, resulting in a potentially exploitable crash.

HIGH 7.5EPSS 1.76%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.76%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

A use-after-free vulnerability can occur when manipulating floating "first-letter" style elements, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 58.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
1.76% probability · 78th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-416
Affected
mozilla/firefox · canonical/ubuntu linux
Source
security@mozilla.org
EPSS trend
0%3%5%27 October 2026: 1.76%27 October 202627 October 2026

EPSS 1.8% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.