Atomicorp WAF Research Note: CVE-2026-34160

Chamilo LMS: Unauthenticated SSRF via PENS Plugin allows attacker to probe internal network and reach cloud metadata ser

CVE Details

• Already protected by existing Atomicorp WAF rules
• Protection status: Understanding Atomicorp WAF Protection Status
• CVE: CVE-2026-34160
• Name: Chamilo LMS: Unauthenticated SSRF via PENS Plugin allows attacker to probe internal network and reach cloud metadata ser
• Severity: High
• CVSS: 8.6 (v3.1) (High)
• CVSS version: 3.1
• CVSS source: GitHub_M CNA
• CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
  • Attack vector: Network
  • Attack complexity: Low
  • Privileges required: None
  • User interaction: None
  • Scope: Changed
  • Confidentiality impact: High
  • Integrity impact: None
  • Availability impact: None
• CWE: CWE-306 — Missing Authentication for Critical Function, CWE-918 — Server-Side Request Forgery (SSRF)
• Related CAPEC attack patterns (via MITRE CWE relationships): CAPEC-12 (opens in a new tab) , CAPEC-166 (opens in a new tab) , CAPEC-216 (opens in a new tab) , CAPEC-36 (opens in a new tab) , CAPEC-62 (opens in a new tab) , CAPEC-664 (opens in a new tab)
• Vendor: chamilo
• Vulnerable product: chamilo lms
• CVE published: 2026-04-14
• CVE last modified: 2026-07-24
• Affected versions (NVD configurations):
  • chamilo lms: <= 1.11.38
  • chamilo lms: 2.0.0 alpha1
  • chamilo lms: 2.0.0 alpha2
  • chamilo lms: 2.0.0 alpha3
  • chamilo lms: 2.0.0 alpha4
  • chamilo lms: 2.0.0 alpha5
  • chamilo lms: 2.0.0 beta1
  • chamilo lms: 2.0.0 beta2
  • chamilo lms: 2.0.0 beta3
  • chamilo lms: 2.0.0 rc1
  • chamilo lms: 2.0.0 rc2
• EPSS: 0.0034; 27.5th percentile (FIRST (opens in a new tab) )
• Latest Update: 2026-09-06
• Selected Rule IDs observed: 337109 , 337110 , 340162 , 340163 , 340165 , 344360 , 347009 , 390722 , 398001 , 398008 , 398021 , 398022
• Matching rules: 12; rules with blocking actions: 10
• Would-block Rule IDs: 337109 , 337110 , 340162 , 340163 , 340165 , 344360 , 347009 , 390722 , 398021 , 398022
• Request surfaces inspected: JSON request data, Request URI, Request argument names, Request arguments, Request cookies, SOAP request data, XML request data

Vulnerability Description

Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, the PENS (Package Exchange Notification Services) plugin endpoint at public/plugin/Pens/pens.php is accessible without authentication and accepts a user-controlled package-url parameter that the server fetches using curl without filtering private or internal IP addresses, enabling unauthenticated Server-Side Request Forgery (SSRF). An attacker can exploit this to probe internal network services, access cloud metadata endpoints (such as 169.254.169.254) to steal IAM credentials and sensitive instance metadata, or trigger state-changing operations on internal services via the receipt and alerts callback parameters. No authentication is required to exploit either SSRF vector, significantly increasing the attack surface. This issue has been fixed in version 2.0.0-RC.3.

Recommended Actions

1. Maintain the observed Atomicorp protections. Keep your Atomicorp commercial rules current and confirm that the selected observed rules (337109 , 337110 , 340162 , 340163 , 340165 , 344360 , 347009 , 390722 , 398021 , 398022 ) have not been locally disabled. Atomicorp commercial rules are enabled by default. If you use Atomic WAF, review the applicable policy and rule settings.

2. Apply the vendor’s remediation. WAF protection is defense in depth and does not replace upgrading or following the affected vendor’s guidance.

   • Affected versions: chamilo chamilo-lms version < 2.0-RC.3.
   • The CVE record does not include written upgrade or workaround instructions, but it does publish the following patch or mitigation reference:
     • Patch or mitigation information (opens in a new tab)
     • Patch or mitigation information (opens in a new tab)

3. Validate after changes. Confirm rule updates are current, review WAF events for the affected application, and test application behavior after vendor upgrades, mitigations, or local policy changes.

Research Notes

Atomicorp WAF protections are designed around attack techniques and exploit behaviors, allowing existing protections to apply across multiple vulnerabilities without requiring a unique rule for every CVE.

Public Vulnerability References

• NVD (opens in a new tab)
• CVE Record (opens in a new tab)
• Patch or mitigation: https://github.com/chamilo/chamilo-lms/commit/de4058d76fac2413afd023b1ec942e8e79579011 (opens in a new tab)
• Patch or mitigation: https://github.com/chamilo/chamilo-lms/releases/tag/v2.0.0-RC.3 (opens in a new tab)
• Vendor advisory: https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-g2xj-4cch-j276 (opens in a new tab)

Test or Research Source

• Source: Atomicorp AI Research Framework
• Tags: cve, derived, ssrf, waf-probe

Research Note Context

This research note documents exploit-technique analysis associated with this vulnerability and references Atomicorp WAF protections observed during engineering review, testing, or validation activities.

Atomicorp security controls are generally designed to identify and mitigate attack techniques and exploit behaviors rather than individual CVE identifiers. As a result, protections developed for one vulnerability may also apply to related attack variants and future vulnerabilities using similar techniques.

Learn More

Atomicorp develops commercially supported security technologies for web applications, servers, endpoints, workloads, and legacy enterprise platforms.

Organizations interested in protecting systems against exploit techniques associated with vulnerabilities such as this one can learn more about:

• Atomic ModSecurity Rules: commercially maintained WAF rules for ModSecurity deployments, including protections for web attacks, bots, scanners, malware, exploitation attempts, and emerging vulnerability classes.
• Atomic WAF: an enterprise web application firewall with Atomicorp rules, centralized management, reporting, authentication controls, and operational tooling.
• Atomic ModSecurity Integrator: a special licensing option for MSPs, MSSPs, OEMs, VARs, reverse proxy providers, and other integrators who want to incorporate Atomicorp ModSecurity rule technology into their own products or services.
• Atomic OSSEC: an enterprise OSSEC-based intrusion detection, compliance, and security monitoring platform.
• Atomic Protector: workload protection for Linux, web, cloud, data center, and hybrid environments.

For additional information, product evaluations, or technical discussions, visit https://www.atomicorp.com/ or https://modsecurity.io/ (opens in a new tab) .