# CVE-2026-26047: moodle DoS — Fixed in 5.1.2

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

# CVE-2026-26047 — moodle

MEDIUM [Fix: moodle/moodle@8683b4a](https://github.com/moodle/moodle/commit/8683b4a04939332e353cad1be51222930dc40b2c)

CVE-2026-26047 is a medium-severity (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in moodle/moodle. A fix is available for moodle/moodle — see the affected versions and patch details below.

Moodle: moodle: uncontrolled resource consumption in tex formula editor leading to denial of service

Also known asBIT-moodle-2026-26047[GHSA-cg8j-5cr2-568q](/vulnerability/GHSA-cg8j-5cr2-568q)

Published

Feb 21, 2026

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

## Exploitation Status

### No confirmed exploitation observed yet

-   CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-26047.

## EPSS Exploitation Probability

[via FIRST.org ↗](https://www.first.org/epss/)

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs43th percentile — riskier than 43% of all scored CVEsHighest risk

0.00%0.36%0.72%1.08%0.1%0.5%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/).

## How urgent is this, really

## Where this sits among everything scored

## Real-World Exposure

3 pkgs affected

🐘`moodle/moodle`🐘`moodle/moodle`🐘`moodle/moodle`

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

## Description

A Denial of Service vulnerability was identified in Moodle’s TeX formula editor. When rendering TeX content using mimetex, insufficient execution time limits could allow specially crafted formulas to consume excessive server resources. An authenticated user could abuse this behavior to degrade performance or cause service interruption.

## Affected Packages

3 total 3 fixed

Ecosystem

Package

Vulnerable range

Fix

🐘Packagist

`moodle/moodle` 

≥ 5.1.0-beta&&< 5.1.2

5.1.2`composer require moodle/moodle:^5.1.2`

🐘Packagist

`moodle/moodle` 

≥ 5.0.0-beta&&< 5.0.5

5.0.5`composer require moodle/moodle:^5.0.5`

🐘Packagist

`moodle/moodle` 

all versions

4.5.9`composer require moodle/moodle:^4.5.9`

## Affected Products

1 product · 3 configurations

Application

`moodle`moodle

≥ 5.1.0 && < 5.1.2

range

## Detection & mitigation playbook

Open-source dependency

1.  ### Detect
    
    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moodle/moodle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
    
2.  ### Fix
    
    Update moodle/moodle to 5.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-26047 is resolved across your whole dependency graph.
    
3.  ### Workarounds
    
    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
    

## Frequently Asked Questions

A Denial of Service vulnerability was identified in Moodle’s TeX formula editor. When rendering TeX content using mimetex, insufficient execution time limits could allow specially crafted formulas to consume excessive server resources. An authenticated user could abuse this behavior to degrade performance or cause service interruption.

O3 Security · Impact-Aware SCA

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