How severe is CVE-2016-2817?

CVE-2016-2817 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2016-2817 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-2817?

CVE-2016-2817 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-2817?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2016-2817 published?

CVE-2016-2817 was published on 2016-04-30 and last updated on 2026-06-17.

CVE-2016-2817

CVE-2016-2817 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 5.4. 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: Medium (CVSS 3.x base score 5.4)
CVSS v2: 4.3
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Mozilla Firefox
Published: 2016-04-30
Last modified: 2026-06-17

Description

The WebExtension sandbox feature in browser/components/extensions/ext-tabs.js in Mozilla Firefox before 46.0 does not properly restrict principal inheritance during chrome.tabs.create and chrome.tabs.update API calls, which allows remote attackers to conduct Universal XSS (UXSS) attacks via a crafted extension that accesses a (1) javascript: or (2) data: URL.

Frequently asked questions

What is CVE-2016-2817?: The WebExtension sandbox feature in browser/components/extensions/ext-tabs.js in Mozilla Firefox before 46.0 does not properly restrict principal inheritance during chrome.tabs.create and chrome.tabs.update API calls, which allows remote attackers to conduct Universal XSS (UXSS) attacks via a crafted extension that accesses a (1) javascript: or (2) data: URL.
How severe is CVE-2016-2817?: CVE-2016-2817 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2016-2817 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-2817?: CVE-2016-2817 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-2817?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2016-2817 published?: CVE-2016-2817 was published on 2016-04-30 and last updated on 2026-06-17.

References

Affected products (1)

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

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