How severe is CVE-2016-5266?

CVE-2016-5266 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2016-5266 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-5266?

CVE-2016-5266 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-5266?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2016-5266 published?

CVE-2016-5266 was published on 2016-08-05 and last updated on 2026-06-17.

CVE-2016-5266

CVE-2016-5266 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-264.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 5.8
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Mozilla Firefox
Published: 2016-08-05
Last modified: 2026-06-17

Description

Mozilla Firefox before 48.0 does not properly restrict drag-and-drop (aka dataTransfer) actions for file: URIs, which allows user-assisted remote attackers to access local files via a crafted web site.

Frequently asked questions

What is CVE-2016-5266?: Mozilla Firefox before 48.0 does not properly restrict drag-and-drop (aka dataTransfer) actions for file: URIs, which allows user-assisted remote attackers to access local files via a crafted web site.
How severe is CVE-2016-5266?: CVE-2016-5266 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2016-5266 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-5266?: CVE-2016-5266 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-5266?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-5266 published?: CVE-2016-5266 was published on 2016-08-05 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*

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