CVE-2019-12835 – CVE-2019-12835 is an out-of-bounds write vulner... (How to Fix)

Q: What is the severity of CVE-2019-12835?

CVE-2019-12835 has a CVSS score of 9.8 (CRITICAL). CVE-2019-12835 is an out-of-bounds write vulnerability in Leanify's XML processing that allows attackers to write controlled data beyond allocated memory boundaries. This affects users of Leanify 0.4.3 who process untrusted XML files. The vulnerability can lead to arbitrary code execution or application crashes.

📋 TL;DR

CVE-2019-12835 is an out-of-bounds write vulnerability in Leanify's XML processing that allows attackers to write controlled data beyond allocated memory boundaries. This affects users of Leanify 0.4.3 who process untrusted XML files. The vulnerability can lead to arbitrary code execution or application crashes.

💻 Affected Systems

Products:

Leanify

Versions: 0.4.3 specifically

Operating Systems: All platforms running Leanify

Default Config Vulnerable: ⚠️ Yes

Notes: Vulnerability triggers when processing XML files containing characters requiring escaping.

📦 What is this software?

Leanify by Leanify Project

View all CVEs affecting Leanify →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution with the privileges of the Leanify process, potentially leading to complete system compromise.

🟠

Likely Case

Application crash (denial of service) or limited memory corruption leading to unpredictable behavior.

🟢

If Mitigated

Minimal impact if proper input validation and memory protections are in place.

🌐 Internet-Facing: MEDIUM - Requires processing attacker-controlled XML files, which is less common for internet-facing services.

🏢 Internal Only: MEDIUM - Internal users could exploit if they can supply malicious XML files to Leanify processes.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Proof of concept available in GitHub issue. Exploitation requires supplying malicious XML to Leanify.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 0.4.4 and later

Vendor Advisory: https://github.com/JayXon/Leanify/issues/52

Restart Required: No

Instructions:

1. Download Leanify 0.4.4 or later from GitHub. 2. Replace existing Leanify binary with patched version. 3. No restart required for standalone tool.

🔧 Temporary Workarounds

Disable XML processing

all

Avoid processing XML files with Leanify until patched

# Use alternative tools for XML compression or avoid XML files

Input validation

all

Validate XML files before processing with Leanify

# Use xmlint or similar to validate XML before Leanify processing

🧯 If You Can't Patch

Restrict Leanify usage to trusted users only
Implement strict file upload controls and sandbox Leanify execution

🔍 How to Verify

Check if Vulnerable:

Check Leanify version: leanify --version. If output shows 0.4.3, system is vulnerable.

Check Version:

leanify --version

Verify Fix Applied:

After updating, run leanify --version and confirm version is 0.4.4 or higher.

📡 Detection & Monitoring

Log Indicators:

Application crashes with memory access violations
Unexpected termination of Leanify processes

Network Indicators:

Unusual file uploads to systems running Leanify

SIEM Query:

process_name:"leanify" AND (event_type:"crash" OR exit_code:139)

📊 Metadata

CVE ID: CVE-2019-12835

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-787

Published: June 15, 2019

Last Updated: November 21, 2024

🔗 References

https://github.com/JayXon/Leanify/issues/52 Exploit,Issue Tracking,Third Party Advisory
https://github.com/JayXon/Leanify/issues/52 Exploit,Issue Tracking,Third Party Advisory

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🔗 Related Vulnerabilities

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