How severe is CVE-2016-2820?

CVE-2016-2820 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2016-2820 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-2820?

CVE-2016-2820 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-2820?

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

When was CVE-2016-2820 published?

CVE-2016-2820 was published on 2016-04-30 and last updated on 2026-06-17.

CVE-2016-2820

CVE-2016-2820 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 4.3. 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-284.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Mozilla Firefox
Published: 2016-04-30
Last modified: 2026-06-17

Description

The Firefox Health Reports (aka FHR or about:healthreport) feature in Mozilla Firefox before 46.0 does not properly restrict the origin of events, which makes it easier for remote attackers to modify sharing preferences by leveraging access to the remote-report IFRAME element.

Frequently asked questions

What is CVE-2016-2820?: The Firefox Health Reports (aka FHR or about:healthreport) feature in Mozilla Firefox before 46.0 does not properly restrict the origin of events, which makes it easier for remote attackers to modify sharing preferences by leveraging access to the remote-report IFRAME element.
How severe is CVE-2016-2820?: CVE-2016-2820 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2016-2820 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-2820?: CVE-2016-2820 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-2820?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2016-2820 published?: CVE-2016-2820 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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