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HIGH · CVSS 8.8 CISA Known Exploited Vulnerability

CVE-2015-4495

Mozilla Firefox Security Feature Bypass Vulnerability

Mozilla Firefox

The PDF reader in Mozilla Firefox before 39.0.3, Firefox ESR 38.x before 38.1.1, and Firefox OS before 2.2 allows remote attackers to bypass the Same Origin Policy, and read arbitrary files or gain privileges, via vectors involving crafted JavaScript code and a native setter, as exploited in the wild in August 2015.

CVSS
8.8
HIGH
EPSS
68.6%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
8 Aug 2015
CWE-346

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 25 May 2022. US federal agencies were required to remediate it by 15 June 2022.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 68.6%, which is higher than 99.3% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2015-4495 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2015-4495.

What does CVE-2015-4495 affect?

CVE-2015-4495 affects Mozilla Firefox. The PDF reader in Mozilla Firefox before 39.0.3, Firefox ESR 38.x before 38.1.1, and Firefox OS before 2.2 allows remote attackers to bypass the Same Origin Policy, and read arbitrary files or gain privileges, via vectors involving crafted JavaScript code and a native setter, as exploited in the wild in August 2015.

How severe is CVE-2015-4495?

CVE-2015-4495 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 68.6%, higher than 99.3% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 15 June 2022.

How should organisations respond to CVE-2015-4495?

Apply the vendor patch for Mozilla Firefox as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.