How severe is CVE-2015-8566?

No CVSS score has been assigned to CVE-2015-8566 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2015-8566?

CVE-2015-8566 affects the following packages: joomla/session (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2015-8566?

Update joomla/session to 1.3.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-8566 is resolved across your whole dependency graph.

How do I detect CVE-2015-8566 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for joomla/session, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2015-8566 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2015-8566 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2015-8566, including 1 documented proof-of-concept exploit on Exploit-DB. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2015-8566?

CVE-2015-8566 has an EPSS (Exploit Prediction Scoring System) score of 8.5%, placing it in the 95th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2015-8566 published, and has it been updated?

CVE-2015-8566 was published on May 17, 2022 and was last updated on December 8, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2015-8566 — session

CVE-2015-8566 is a remote code execution vulnerability in joomla/session. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for joomla/session — see the affected versions and patch details below.

Joomla! Framework Remote Code Injection Vulnerability

Published

May 17, 2022

Updated

Dec 8, 2024

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

8.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs95th percentile — riskier than 95% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐘joomla/session

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

The Session package 1.x before 1.3.1 for Joomla! Framework allows remote attackers to execute arbitrary code via unspecified session values.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`joomla/session`	all versions	1.3.1`composer require joomla/session:^1.3.1`

Affected Products

1 product · 1 configurations

Application

sessionjoomla

1 version

1.3.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-39033webappsphp

Joomla! 1.5 < 3.4.6 - Object Injection 'x-forwarded-for' Header Remote Code Execution

by Andrew McNicol · Dec 18, 2015

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for joomla/session, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update joomla/session to 1.3.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-8566 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

The Session package 1.x before 1.3.1 for Joomla! Framework allows remote attackers to execute arbitrary code via unspecified session values.

O3 Security · Impact-Aware SCA

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