CVE-2020-14322Public exploitNetwork attack vector

Unauthenticated denial of service via unbounded combo loading

Published Aug 16, 2022 · Updated Aug 4, 2024

Denial of service in Moodle LMS before 3.9.1, 3.8.4, 3.7.7, and 3.5.13 allows remote attackers to interrupt service. The theme/yui_combo.php endpoint accepts a combo request containing an unbounded list of files and loads their contents into one response. No authentication or user interaction is required; repeated oversized combo requests exhaust server resources and degrade or stop the web application.

CVSS severity7.5
High
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Moodle LMS before 3.9.1, 3.8.4, 3.7.7, and 3.5.13 allows remote attackers to interrupt service. The theme/yui_combo.php endpoint accepts a combo request containing an unbounded list of files and loads their contents into one response. No authentication or user interaction is required; repeated oversized combo requests exhaust server resources and degrade or stop the web application.

The record

CVE
CVE-2020-14322
Published
Aug 16, 2022
Updated
Aug 4, 2024
Vendor
Moodle
Product
Moodle LMS
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 16, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 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=Moodle 3.9, 3.8 to 3.8.3, 3.7 to 3.7.6, 3.5 to 3.5.12 and earlier unsupported versions

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Moodle · Moodle LMSversion=Moodle 3.9, 3.8 to 3.8.3, 3.7 to 3.7.6, 3.5 to 3.5.12 and earlier unsupported versions

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

Public exploit references

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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