Cyber Resilience

CVE-2016-8870

Joomla\! ≤ 3.6.3

Public PoCHigh EPSS
Published
04 November 2016
Modified
06 May 2026
Patch / advisory
CVSS Score v3 8.1
Click a component to see what it means
Raw vectorCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.81 99.6th percentile
Risk Priority 81 floored blend · peak EPSS

Summary

CVE-2016-8870 is a high-severity Improper Input Validation (CWE-20) vulnerability in Joomla Joomla\!. Its CVSS base score is 8.1 (High).

Operationally, ranked in the top 0.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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.

CWE(s)

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1136.001 Local Account Persistenceconfidence: HIGH
The vulnerability allows creation of user accounts without proper authorization checks, directly enabling local account creation.
T1078.003 Local Accounts Stealthconfidence: MEDIUM
Newly created accounts can be used as valid local accounts for subsequent access or actions.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2016-8869Same product: Joomla Joomla\!
CVE-2023-23754Same product: Joomla Joomla\!
CVE-2026-35223Same product: Joomla Joomla\!
CVE-2023-23751Same product: Joomla Joomla\!
CVE-2026-48958Same product: Joomla Joomla\!
CVE-2017-8917Same product: Joomla Joomla\!
CVE-2024-21726Same product: Joomla Joomla\!
CVE-2026-35221Same product: Joomla Joomla\!
CVE-2023-23752Same product: Joomla Joomla\!
CVE-2024-21724Same product: Joomla Joomla\!

Affected Assets

joomla
joomla\!
≤ 3.6.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require and enforce input validation during development.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

prevents

Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.

prevents

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

prevents

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

none

Regular automated validation of system software and data content, combined with scanning of all inbound files, enforces input validation at the boundary before untrusted content is processed.

References