VulnTideExploited vulnerabilities, by vendor. Data as of 28 Oct 2026.
Known exploitedIn CISA's KEV catalog since 25 May 2022Ransomware use: unknown
Mozilla Firefox

CVE-2015-4495: Mozilla Firefox Security Feature Bypass Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 25 May 2022, 2,482 days after the CVE record was published.

How likely is exploitation in the next 30 days?
68.6%

EPSS score, percentile 99.3 of all scored records

How severe?
8.8 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA deadline 15 Jun 2022. Apply updates per vendor instructions.

Advisories and patches (9)

Which versions are affected?

Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Required action, set by CISA

Apply updates per vendor instructions.

CISA due date for this action: 15 June 2022.

Advisories and patches

Linked from CISA's catalog entry

Affected products and versions

The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Moxilla Firefox allows remote attackers to bypass the Same Origin Policy to read arbitrary files or gain privileges.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

  • CISA added CVE-2015-4495 to its Known Exploited Vulnerabilities (KEV) catalog on 25 May 2022.
  • CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
  • The due date CISA sets for the required action is 15 Jun 2022.
  • The CVE record was published on 8 Aug 2015, 2,482 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 8.8 (High), taken from CISA's enrichment of the record.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 68.6% (percentile 99.3), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
8 Aug 2015CVE record published
25 May 2022Added to CISA KEV
15 Jun 2022CISA due date for the required action
21 Oct 2025CVE record last updated

References

5 more in the CVE record.

More exploited Mozilla vulnerabilities

  • CVE-2010-3765: Mozilla Multiple Products Remote Code Execution Vulnerability (added 6 Oct 2025)
  • CVE-2024-9680: Mozilla Firefox Use-After-Free Vulnerability (added 15 Oct 2024)
  • CVE-2016-9079: Mozilla Firefox, Firefox ESR, and Thunderbird Use-After-Free Vulnerability (added 22 Jun 2023)
  • CVE-2019-11707: Mozilla Firefox and Thunderbird Type Confusion Vulnerability (added 23 May 2022)
  • CVE-2019-11708: Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability (added 23 May 2022)
  • CVE-2013-1690: Mozilla Firefox and Thunderbird Denial-of-Service Vulnerability (added 28 Mar 2022)