CVE-2023-28333Network attack vector

Template injection via double-rendered pix component

Published Mar 23, 2023 · Updated Aug 2, 2024

Mustache injection in affected Moodle LMS releases allows attackers to alter template rendering through a crafted pix helper component. The mustache_pix_helper::pix method rendered its component argument during parsing and then rendered it again, evaluating syntax introduced by the first pass. Reachability requires a plugin or theme to combine the helper with user input; Moodle reported no exploitable use in core LMS, limiting exposure to extensions that do so.

CVSS severity9.8
Critical
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Mustache injection in affected Moodle LMS releases allows attackers to alter template rendering through a crafted pix helper component. The mustache_pix_helper::pix method rendered its component argument during parsing and then rendered it again, evaluating syntax introduced by the first pass. Reachability requires a plugin or theme to combine the helper with user input; Moodle reported no exploitable use in core LMS, limiting exposure to extensions that do so.

The record

CVE
CVE-2023-28333
Published
Mar 23, 2023
Updated
Aug 2, 2024
Vendor
Moodle
Product
Moodle LMS
Classifications
CWE-94
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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 <3.9.20
  2. Affected versionversion=3.11.0 <3.11.13
  3. Affected versionversion=4.0.0 <4.0.7
  4. Affected versionversion=4.1.0 <4.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Moodle · Moodle LMSversion=0 <3.9.20; version=3.11.0 <3.11.13; version=4.0.0 <4.0.7; version=4.1.0 <4.1.2

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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