Is CVE-2026-27807 in the CISA KEV catalog?

No. CVE-2026-27807 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-27807?

CVE-2026-27807 has a CVSS v3 base score of 4.9 (MEDIUM).

What is the EPSS score for CVE-2026-27807?

CVE-2026-27807 has an EPSS score of 0.28% (20th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-27807?

Upgrade markus to 2.9.4 or later.

CVE & CISA-KEV Catalog

CVE-2026-27807

MEDIUM

4.9

CVSS v3

NVD

Description

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.

CWE-776

How to fix

Remediation Available

markusNVD

Affected:< 2.9.4Fixed in:2.9.4CVE-2026-27807derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.28%probability of exploitation in 30 days

20thpercentile

Low risk: more likely to be exploited than 20% of all known CVEs.

References

Vendor Advisory1

github.com

Release Notes1

github.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-12.