How severe is CVE-2016-8870?

CVE-2016-8870 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-8870 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 82% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-8870?

CVE-2016-8870 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-8870?

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-2016-8870 published?

CVE-2016-8870 was published on 2016-11-04 and last updated on 2026-06-17.

CVE-2016-8870

CVE-2016-8870 is a high-severity vulnerability in Joomla Joomla! with a CVSS 3.x base score of 8.1. Its EPSS exploit-prediction score of 82% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 6.8
EPSS exploit prediction: 82% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Joomla Joomla!
Published: 2016-11-04
Last modified: 2026-06-17

Description

The register method in the UsersModelRegistration class in controllers/user.php in the Users component in Joomla! before 3.6.4, when registration has been disabled, allows remote attackers to create user accounts by leveraging failure to check the Allow User Registration configuration setting.

Frequently asked questions

What is CVE-2016-8870?: The register method in the UsersModelRegistration class in controllers/user.php in the Users component in Joomla! before 3.6.4, when registration has been disabled, allows remote attackers to create user accounts by leveraging failure to check the Allow User Registration configuration setting.
How severe is CVE-2016-8870?: CVE-2016-8870 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-8870 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 82% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-8870?: CVE-2016-8870 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-8870?: 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-2016-8870 published?: CVE-2016-8870 was published on 2016-11-04 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:joomla:joomla\!:*:*:*:*:*:*:*:*

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