What is the CVSS score of CVE-2021-41691?

CVE-2021-41691 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.4%.

Which versions of PHP are affected by CVE-2021-41691?

A critical SQL injection vulnerability in OS4Ed v8.0 allows unauthenticated attackers to compromise student records and institutional data through a publicly accessible endpoint.

Is there a public PoC exploit available for CVE-2021-41691?

Yes, a public proof-of-concept exploit is available for CVE-2021-41691. Prioritise patching immediately. EPSS: 2.4%.

How to fix or mitigate CVE-2021-41691?

Within 24 hours: Inventory all OS4Ed v8.0 instances and isolate affected systems from production networks or disable the TransferredOutModal.php endpoint. Within 7 days: Implement WAF rules blocking malicious SQL syntax in the student_id and TRANSFER[SCHOOL] parameters, conduct forensic audit of access logs for exploitation attempts, and evaluate emergency vendor patches or workarounds. Within 30 days: Migrate to a patched OS4Ed version, perform full security assessment of the application, and implement input validation and parameterized queries across all endpoints.

PHP CVE-2021-41691

EUVD-2021-28703 CRITICAL

SQL Injection (CWE-89)

2025-06-24 cve@mitre.org

PHP SQLi Opensis Os4Ed

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

EUVD ID Assigned

Mar 15, 2026 - 22:36 euvd

EUVD-2021-28703

Analysis Generated

Mar 15, 2026 - 22:36 vuln.today

CVE Published

Jun 24, 2025 - 16:15 nvd

CRITICAL 9.8

DescriptionCVE.org

A SQL injection vulnerability exists in OS4Ed Open Source Information System Community v8.0 via the "student_id" and "TRANSFER{SCHOOL]" parameters in POST request sent to /TransferredOutModal.php.

AnalysisAI

A remote code execution vulnerability in OS4Ed Open Source Information System Community (CVSS 9.8). Critical severity with potential for significant impact on affected systems.

Technical ContextAI

CWE-89 (SQL Injection). CVSS 9.8 indicates critical severity with likely remote exploitation vector. Affects OS4Ed Open Source Information System Community.