CVE-2023-5547Network attack vector

Script execution via unescaped course preview fields

Published Nov 9, 2023 · Updated Sep 4, 2024

Stored cross-site scripting in affected Moodle LMS releases allows attackers to run script in a course-upload preview viewer's browser. The upload-course tracker's output method placed shortname, fullname, and idnumber values into HTML table cells without applying Moodle's s() escaping. An attacker must supply unsafe course data and a user must open its preview; the resulting script runs in that viewer's Moodle origin.

CVSS severity6.1
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in affected Moodle LMS releases allows attackers to run script in a course-upload preview viewer's browser. The upload-course tracker's output method placed shortname, fullname, and idnumber values into HTML table cells without applying Moodle's s() escaping. An attacker must supply unsafe course data and a user must open its preview; the resulting script runs in that viewer's Moodle origin.

The record

CVE
CVE-2023-5547
Published
Nov 9, 2023
Updated
Sep 4, 2024
Vendor
Moodle
Product
Moodle LMS
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.9.24
  2. Affected versionversion=3.11.0 <3.11.17
  3. Affected versionversion=4.0.0 <4.0.11
  4. Affected versionversion=4.1.0 <4.1.6
  5. Affected versionversion=4.2.0 <4.2.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Moodle · Moodle LMSversion=0 <3.9.24; version=3.11.0 <3.11.17; version=4.0.0 <4.0.11; version=4.1.0 <4.1.6; version=4.2.0 <4.2.3

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
3.3Fedora ProjectCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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