CVE-2026-26047Network attack vector

Service interruption via unbounded mimetex execution

Published Feb 21, 2026 · Updated Feb 21, 2026

Resource exhaustion in Moodle LMS 5.1.1 and earlier allows remote authenticated users to interrupt service via crafted TeX formulas. The TeX filter passes formula input to the mimetex process without an execution deadline, allowing a crafted expression to keep consuming server resources until it finishes. Exploitation requires an authenticated account and the mimetex renderer; repeated slow renders can degrade performance or interrupt the application.

CVSS severity6.5
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Moodle LMS 5.1.1 and earlier allows remote authenticated users to interrupt service via crafted TeX formulas. The TeX filter passes formula input to the mimetex process without an execution deadline, allowing a crafted expression to keep consuming server resources until it finishes. Exploitation requires an authenticated account and the mimetex renderer; repeated slow renders can degrade performance or interrupt the application.

The record

CVE
CVE-2026-26047
Published
Feb 21, 2026
Updated
Feb 21, 2026
Vendor
Moodle
Product
Moodle LMS
Classifications
CWE-400, CWE-770, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 21, 2026Record 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 <4.5.9
  2. Affected versionversion=5.0.0 <5.0.5
  3. Affected versionversion=5.1.0 <5.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Moodle · Moodle LMSversion=0 <4.5.9; version=5.0.0 <5.0.5; version=5.1.0 <5.1.2

Published CVSS scores

6.5Fedora ProjectCVSS:3.1/AV:N/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

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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