Moodle HTML Data Format HTML injection

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.1$5k-$25k0.00

Summaryinfo

A vulnerability was found in Moodle. It has been classified as problematic. The affected element is an unknown function of the component HTML Data Format Handler. The manipulation leads to HTML injection. This vulnerability is uniquely identified as CVE-2021-36401. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Moodle (Learning Management Software) (unknown version). This issue affects an unknown code block of the component HTML Data Format Handler. The manipulation with an unknown input leads to a html injection vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

In Moodle, ID numbers exported in HTML data formats required additional sanitizing to prevent a local stored XSS risk.

The weakness was disclosed 03/07/2023. The advisory is shared at moodle.org. The identification of this vulnerability is CVE-2021-36401 since 07/12/2021. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/06/2025). MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2023-1009). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.1
VulDB Meta Temp Score: 4.1

VulDB Base Score: 3.5
VulDB Temp Score: 3.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 4.8
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: HTML injection
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

07/12/2021 🔍
03/07/2023 +603 days 🔍
03/07/2023 +0 days 🔍
07/06/2025 +852 days 🔍

Sourcesinfo

Product: moodle.org

Advisory: moodle.org
Status: Confirmed

CVE: CVE-2021-36401 (🔍)
GCVE (CVE): GCVE-0-2021-36401
GCVE (VulDB): GCVE-100-222437
EUVD: 🔍

Entryinfo

Created: 03/07/2023 08:40
Updated: 07/06/2025 16:46
Changes: 03/07/2023 08:40 (37), 03/07/2025 21:39 (25), 07/06/2025 16:46 (1)
Complete: 🔍
Cache ID: 216::103

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