CVE-2025-4077: School Billing System Buffer Overflow Flaw

CVE-2025-4077 Overview

CVE-2025-4077 is a stack-based buffer overflow vulnerability in code-projects School Billing System 1.0. The flaw resides in the searchrec function and is triggered by manipulation of the Name argument. An authenticated local attacker can exploit the issue to corrupt stack memory on the host running the application. Public disclosure of the exploit has occurred, increasing the risk of opportunistic use against unpatched installations. The vulnerability maps to CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-787 (Out-of-bounds Write).

Critical Impact
A local attacker with low privileges can trigger a stack-based buffer overflow through the searchrec function, potentially causing memory corruption and application crashes.

Affected Products

code-projects School Billing System 1.0
Vendor: Fabian (fabian:school_billing_system:1.0)
Vulnerable component: searchrec function processing the Name argument

Discovery Timeline

2025-04-29 - CVE-2025-4077 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-4077

Vulnerability Analysis

The vulnerability is a stack-based buffer overflow in the searchrec function of code-projects School Billing System 1.0. The function accepts a Name argument and writes it into a fixed-size stack buffer without enforcing length validation. When the supplied input exceeds the buffer size, adjacent stack memory is overwritten. This can corrupt saved return addresses, frame pointers, or local variables. Exploitation requires local access and low-privileged authentication on the host running the application. The exploit has been publicly disclosed via VulDB entry #306514 and a GitHub advisory, lowering the barrier to reproduction.

Root Cause

The root cause is missing bounds checking on the Name input before it is copied into a stack-allocated buffer inside searchrec. This aligns with CWE-119 and CWE-787, where an out-of-bounds write occurs during string handling. Common C library functions such as strcpy, sprintf, or gets are typical sources of this pattern when used against fixed-size buffers.

Attack Vector

An attacker must have local access and low-level privileges on the system running the School Billing System. The attacker invokes the searchrec function through the application's search workflow and supplies an oversized value in the Name field. The overflow corrupts stack memory, at minimum causing a denial of service through application crash. Detailed reproduction steps are documented in the GitHub CVE Documentation.

No verified proof-of-concept code is reproduced here. Refer to the VulDB #306514 CTI Report for technical exploitation details.

Detection Methods for CVE-2025-4077

Indicators of Compromise

Unexpected termination or crash of the School Billing System process shortly after user input in search functionality
Core dump or crash reports referencing the searchrec function or overflown stack frames
Local user accounts submitting abnormally long values into the Name search field

Detection Strategies

Monitor process crash telemetry for school_billing_system.exe (or platform equivalent) on hosts where the application is deployed
Deploy behavioral endpoint monitoring to identify anomalous child-process creation or memory manipulation originating from the School Billing System binary
Review application logs for oversized Name search queries preceding process termination

Monitoring Recommendations

Baseline normal input length for the Name field and alert on entries exceeding expected bounds
Enable operating system crash reporting (Windows Error Reporting or coredump on Linux) to capture exploit attempts
Track local logon activity on systems hosting the application and correlate with application faults

How to Mitigate CVE-2025-4077

Immediate Actions Required

Restrict local access to systems running code-projects School Billing System 1.0 to trusted, authenticated users only
Remove the application from production environments where it is not required, given the lack of a vendor patch
Enforce least-privilege on local accounts to reduce the impact of exploitation

Patch Information

No vendor patch is currently referenced in the NVD entry or vendor resources. Users should monitor the Code Projects Resource Hub for updates. Because code-projects School Billing System is distributed primarily as an educational project, organizations should consider replacing it with a maintained alternative if used in production.

Workarounds

Isolate the application on dedicated hosts with restricted local logon rights
Compile the source with modern stack protections (-fstack-protector-strong, -D_FORTIFY_SOURCE=2, ASLR, DEP) if rebuilding from source is feasible
Apply input length validation on the Name field at the application layer as a source-level fix, replacing unsafe string functions with bounded equivalents such as strncpy or snprintf

bash

# Example hardening flags when rebuilding from source
gcc -O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2 \
    -Wformat -Wformat-security -fPIE -pie \
    -Wl,-z,relro,-z,now -o school_billing school_billing.c