Moodle up to 2.1.2 Subsystem missing encryption

CVSS Meta Temp Score
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CTI Interest Score
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A vulnerability was found in Moodle (Learning Management Software) and classified as problematic. This issue affects an unknown functionality of the component Subsystem. The manipulation with an unknown input leads to a missing encryption vulnerability. Using CWE to declare the problem leads to CWE-311. The product does not encrypt sensitive or critical information before storage or transmission. Impacted is integrity. The summary by CVE is:

CRLF injection vulnerability in calendar/set.php in the Calendar subsystem in Moodle 1.9.x before 1.9.15, 2.0.x before 2.0.6, and 2.1.x before 2.1.3 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via unspecified vectors.

The weakness was shared 07/20/2012 by Ryan Smith (Patrick) as confirmed git commit (GIT Repository). The advisory is shared at The identification of this vulnerability is CVE-2011-4586 since 11/29/2011. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1600 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 58172 (Debian DSA-2421-1 : moodle - several vulnerabilities), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks.

Upgrading to version 1.9.3 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at The best possible mitigation is suggested to be patching the affected component.

The vulnerability is also documented in the vulnerability database at Tenable (58172). The entries 61356, 61351, 61350 and 61348 are related to this item.






CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍



VulDB Base Score: 🔍
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NVD Base Score: 🔍


Class: Missing encryption
CWE: CWE-311 / CWE-310
ATT&CK: T1600

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Nessus ID: 58172
Nessus Name: Debian DSA-2421-1 : moodle - several vulnerabilities
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍

OpenVAS ID: 71149
OpenVAS Name: Debian Security Advisory DSA 2421-1 (moodle)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Upgrade: Moodle 1.9.3
Patch: 581e8dba387f090d89382115fd850d8b44351526


11/29/2011 🔍
12/06/2011 +7 days 🔍
01/02/2012 +27 days 🔍
07/20/2012 +200 days 🔍
07/20/2012 +0 days 🔍
07/22/2012 +2 days 🔍
03/23/2015 +974 days 🔍
12/06/2021 +2450 days 🔍



Advisory: DSA-2421
Researcher: Ryan Smith (Patrick)
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2011-4586 (🔍)

Vulnerability Center: 35607 - Calendar Subsystem in Moodle Allows Remote CRLF Injection via Unspecified Vectors, Medium
SecurityFocus: 50923 - Moodle Multiple Security Vulnerabilities

See also: 🔍


Created: 03/23/2015 04:50 PM
Updated: 12/06/2021 02:28 PM
Changes: 03/23/2015 04:50 PM (60), 04/14/2017 02:34 PM (13), 12/06/2021 02:23 PM (4), 12/06/2021 02:25 PM (1), 12/06/2021 02:28 PM (2)
Complete: 🔍


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