Public proof of conceptFix available

CVE-2016-8870

A public proof of concept exists; no exploitation attested.

Published2016-11-04
WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2016-11-0421:59CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2016-8870?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2016-8870?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Joomla

Branch	Affected	Fixed in	Source
3.6	≤ 3.6.3	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

developer.joomla.orgVendor Advisory
github.comPatch

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedcved-sources/cve-2016-8870

Sources

NVDCVSS 3.08.1read 2026-10-23
NVDCVSS 2.06.8read 2026-10-23
NVDweakness (CWE)CWE-20read 2026-10-23
FIRST EPSSEPSS score81.1 %read 2026-10-23
PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2016-11-04
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2016-8870?

Is CVE-2016-8870 actively exploited?

Active exploitation of CVE-2016-8870 has not been confirmed. Its EPSS score was 81.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2016-8870?

CVE-2016-8870 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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