Name: CVE-2021-47857: Improper Neutralization of Input During Web Page Generation
Creator: Rapid7
Published: 2026-01-21T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2021-47857, CVSS 7.2, EPSS 0.00369

Moodle 3.10.3 contains a persistent cross-site scripting vulnerability in the calendar event subtitle field that allows attackers to inject malicious scripts. Attackers can craft a calendar event with malicious JavaScript in the subtitle track label to execute arbitrary code when users view the event.

CVSS Details

CVSS 4.0 Base Score: 5.1 (MEDIUM)
CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
CVSS 3.1 Base Score: 7.2
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Moodle	—	Upgrade to the latest version of Moodle	Apr 7, 2026	Jan 21, 2026

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CVSS Details

Covered by Rapid7

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