CVE-2026-0955

Executive Summary

CVE-2026-0955 is a high-severity memory corruption vulnerability in Digilent DASYLab, a data acquisition and analysis software. The flaw is an out-of-bounds read that occurs when the application loads a specially crafted, corrupted file. Successful exploitation could lead to information disclosure or arbitrary code execution. The attack vector is local, requiring user interaction (opening a malicious file). No patch is currently available, and no public proof-of-concept (PoC) or exploit code has been released. The EPSS score is 0.0%, indicating a very low probability of exploitation in the wild at this time.

CVSS Breakdown & Threat Level

• CVSS Score: 7.8 (High)
• Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Attack Vector (AV): Local (L) – The attacker must have local access to the system.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No privileges needed to trigger the vulnerability.
• User Interaction (UI): Required (R) – The victim must open the malicious file.
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality (C): High (H) – Potential for full information disclosure.
• Integrity (I): High (H) – Potential for arbitrary code execution.
• Availability (A): High (H) – Potential for system crash or compromise.

Threat Level: High. While no active exploitation is reported, the potential for arbitrary code execution makes this a critical risk for organizations using DASYLab.

Deep Dive & Mechanics

The vulnerability is an out-of-bounds read (CWE-125) in the file parsing logic of Digilent DASYLab. When the application loads a corrupted file, it fails to properly validate the size or bounds of a data structure, leading to a read operation that accesses memory beyond the allocated buffer. This can leak sensitive information or, if the read data is used in a subsequent operation (e.g., as a pointer or jump target), lead to arbitrary code execution.

The root cause is likely insufficient input validation during file parsing. The attacker crafts a file with malformed headers or data fields that cause the parser to read past the intended buffer. The exact vulnerable function is not publicly documented, but the behavior is consistent with classic memory corruption in desktop applications.

Vulnerable vs. Patched Code

No patch is available. The vulnerable code is in the file parsing routines of DASYLab. A hypothetical fix would involve adding bounds checks before every read operation from the file buffer. For example:

Vulnerable (pseudo-code):

void parse_file(char *buffer, size_t size) {
    int data_size = *(int*)buffer; // read size from file
    char *data = buffer + 4;
    // No check if data_size exceeds remaining buffer
    process_data(data, data_size);
}

Patched (pseudo-code):

void parse_file(char *buffer, size_t size) {
    if (size < 4) return;
    int data_size = *(int*)buffer;
    if (data_size < 0 || data_size > size - 4) return; // bounds check
    char *data = buffer + 4;
    process_data(data, data_size);
}

Exploitation & Lab Setup

Red Team (Exploitation)

Objective: Achieve arbitrary code execution by crafting a malicious DASYLab file.

Lab Setup:

• Target: Windows 10/11 with Digilent DASYLab installed (any version).
• Tools: Python (for file crafting), debugger (x64dbg), fuzzer (optional).

Steps:

1. Analyze File Format: Reverse engineer the DASYLab file format to identify the vulnerable field. Use a debugger to trace file loading and find the out-of-bounds read.
2. Craft Malicious File: Create a file with a manipulated size field that causes the parser to read beyond the buffer. Overwrite the data with controlled values to hijack execution flow (e.g., overwrite a function pointer or return address).
3. Deliver Payload: Send the file via email, download link, or USB drive. Convince the user to open it.
4. Execute: When the user opens the file, the vulnerability triggers, leading to code execution.

Note: No public exploit exists. This is a theoretical approach.

Blue Team (Defense)

Detection:

• Monitor for unusual file opens by DASYLab.exe.
• Use endpoint detection and response (EDR) to detect memory corruption events (e.g., access violations).
• Deploy file integrity monitoring (FIM) on DASYLab installation directories.

Prevention:

• Restrict execution of DASYLab to trusted users only.
• Use application whitelisting to prevent unknown binaries.
• Implement strict file upload/download policies to block .dasy files from untrusted sources.

Mitigation:

• If possible, use a sandbox or virtualized environment to run DASYLab.
• Monitor for CVEs and apply patches as soon as they become available.

Indicators of Compromise (IOCs)

• File Hashes: (No known malicious files yet)
• Process: DASYLab.exe with abnormal memory access patterns.
• Network: Outbound connections from DASYLab.exe (if code execution leads to C2).
• Registry: Unusual modifications to DASYLab settings.
• File System: Presence of .dasy files with unusual sizes or structures.

Detection Engineering

YARA Rule

rule CVE_2026_0955_DASYLab_Corrupted_File {
    meta:
        description = "Detects potentially malicious DASYLab files exploiting CVE-2026-0955"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "unknown"
    strings:
        $magic = { 44 41 53 59 } // "DASY" magic bytes (example)
        $suspicious_size = { FF FF FF 7F } // example of large size field
    condition:
        $magic at 0 and $suspicious_size
}

Sigma Rule

title: CVE-2026-0955 DASYLab Memory Corruption
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects potential exploitation of CVE-2026-0955 via abnormal process behavior
author: Valters IT
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\DASYLab.exe'
        CommandLine|contains: '.dasy'
    condition: selection
falsepositives:
    - Legitimate use of DASYLab
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2026-0955 DASYLab Potential C2"; flow:to_server,established; content:"|44 41 53 59|"; depth:4; content:"|FF FF FF 7F|"; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate: If DASYLab is not critical, remove it from all systems.
2. Restrict Access: Limit DASYLab usage to authorized personnel only.
3. Monitor: Enable enhanced logging and monitoring for DASYLab processes.

Long-Term:

1. Patch: Await an official patch from Digilent. Monitor their security advisories.
2. Alternative: Consider using alternative data acquisition software that is actively maintained.
3. Training: Educate users on the risks of opening untrusted files.

Workaround: None available. The vulnerability is in the file parsing logic and cannot be easily mitigated without a patch.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert