Is there a public PoC exploit available for CVE-2026-16155?

Yes, a public proof-of-concept exploit is available for CVE-2026-16155. Prioritise patching immediately. EPSS: 0.2%.

Exam Timetabling System CVE-2026-16155

Q: What is the CVSS score of CVE-2026-16155?

CVE-2026-16155 has a CVSS 4.0 base score of 2.0 (Low). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.2%.

LOW

Cross-site Scripting (XSS) (CWE-79)

2026-07-18 VulDB

PHP XSS Class And Exam Timetabling System Sourcecodester

2.0

CVSS 4.0 · Vendor: VulDB

Severity by source

Vendor (VulDB) PRIMARY

2.0 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

5.4 MEDIUM

Network-accessible XSS requiring low-privilege auth (PR:L) and victim interaction (UI:R); scope changes to victim browser with low C and I impact.

3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

4.0 AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Primary rating from Vendor (VulDB).

CVSS VectorVendor: VulDB

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Scope

Lifecycle Timeline

Analysis Generated

Jul 18, 2026 - 21:35 vuln.today

Severity Changed

Jul 18, 2026 - 21:22 NVD

MEDIUM LOW

CVSS changed

Jul 18, 2026 - 21:22 NVD

5.1 (MEDIUM) 2.0 (LOW)

CVE Published

Jul 18, 2026 - 20:45 cve.org

LOW 2.0

DescriptionCVE.org

A vulnerability was identified in SourceCodester Class and Exam Timetabling System 1.0. Affected by this issue is some unknown functionality of the file /schoolyr.php. The manipulation of the argument sy leads to cross site scripting. It is possible to initiate the attack remotely. The exploit is publicly available and might be used.

AnalysisAI

Cross-site scripting in SourceCodester Class and Exam Timetabling System 1.0 allows authenticated remote attackers to inject arbitrary JavaScript into the browsers of other users by manipulating the sy parameter in /schoolyr.php. The vulnerability is a stored or reflected XSS (CWE-79) in a PHP-based academic scheduling application. A publicly available exploit exists on GitHub, though no active exploitation has been confirmed by CISA KEV, and the low CVSS 4.0 score of 2.0 reflects the limited real-world impact constrained by authentication requirements and required user interaction.

Technical ContextAI

The affected product is the SourceCodester Class and Exam Timetabling System version 1.0, a PHP-based web application for academic scheduling, identified by CPE cpe:2.3:a:sourcecodester:class_and_exam_timetabling_system:*:*:*:*:*:*:*:*. The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), meaning the application fails to sanitize or encode user-supplied input in the sy parameter before reflecting or rendering it in the HTTP response within /schoolyr.php. This class of flaw arises when PHP applications directly interpolate untrusted GET/POST parameters into HTML output without applying htmlspecialchars() or equivalent encoding, enabling script injection into the victim's browser DOM context.

RemediationAI

No vendor-released patch has been identified at time of analysis for SourceCodester Class and Exam Timetabling System 1.0. The primary remediation is manual code-level mitigation: developers should apply htmlspecialchars($sy, ENT_QUOTES, 'UTF-8') (or equivalent output encoding) before rendering the sy parameter in /schoolyr.php. As a compensating control, deploying a Content Security Policy (CSP) header - specifically Content-Security-Policy: script-src 'self' - will block inline script execution injected via XSS, though this may break legitimate inline scripts in the application. Restricting access to /schoolyr.php to trusted internal networks reduces exposure for institutions where timetabling is an internal tool. References for disclosure context are available at https://vuldb.com/cve/CVE-2026-16155 and the public exploit is documented at https://github.com/justconter/cve/issues/4.