MarkUsProject Markus up to 2.9.3 YAML File Parser xml entity expansion

CVSS Meta Temp Score
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CTI Interest Score
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3.7$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in MarkUsProject Markus up to 2.9.3. The impacted element is an unknown function of the component YAML File Parser. Executing a manipulation can lead to xml entity expansion. This vulnerability is tracked as CVE-2026-27807. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in MarkUsProject Markus up to 2.9.3 and classified as problematic. This vulnerability affects an unknown code block of the component YAML File Parser. The manipulation with an unknown input leads to a xml entity expansion vulnerability. The CWE definition for the vulnerability is CWE-776. The product uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities. As an impact it is known to affect availability. CVE summarizes:

MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.4, MarkUs allows course instructors to upload YAML files to create/update various entities (e.g., assignment settings). These YAML files are parsed with aliases enabled. This issue has been patched in version 2.9.4.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-27807 since 02/24/2026. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are required for exploitation. There are neither technical details nor an exploit publicly available.

Upgrading to version 2.9.4 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Type

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.8
VulDB Meta Temp Score: 3.7

VulDB Base Score: 2.7
VulDB Temp Score: 2.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.9
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Xml entity expansion
CWE: CWE-776
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Markus 2.9.4

Timelineinfo

02/24/2026 CVE reserved
03/06/2026 +10 days Advisory disclosed
03/06/2026 +0 days VulDB entry created
03/12/2026 +6 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-m9rx-85mx-q9h6
Status: Confirmed

CVE: CVE-2026-27807 (🔒)
GCVE (CVE): GCVE-0-2026-27807
GCVE (VulDB): GCVE-100-349312

Entryinfo

Created: 03/06/2026 07:04
Updated: 03/12/2026 19:00
Changes: 03/06/2026 07:04 (67), 03/12/2026 19:00 (1)
Complete: 🔍
Cache ID: 216::103

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