CVE-2021-42859 – A memory leak vulnerability in Mini-XML v3.2 co... (How to Fix)

Q: What is the severity of CVE-2021-42859?

CVE-2021-42859 has a CVSS score of 7.5 (HIGH). A memory leak vulnerability in Mini-XML v3.2 could allow attackers to cause denial of service by exhausting system memory. This affects applications using the vulnerable Mini-XML library for XML parsing. The impact is limited to DoS rather than code execution.

📋 TL;DR

A memory leak vulnerability in Mini-XML v3.2 could allow attackers to cause denial of service by exhausting system memory. This affects applications using the vulnerable Mini-XML library for XML parsing. The impact is limited to DoS rather than code execution.

💻 Affected Systems

Products:

Mini-XML (mxml)

Versions: Version 3.2 (testing reports inconsistent about other versions)

Operating Systems: All platforms where Mini-XML is used

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects applications that use Mini-XML library for XML parsing. Inconsistent testing reports about exact version impact.

📦 What is this software?

Mini Xml by Mini Xml Project

View all CVEs affecting Mini Xml →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system unavailability due to memory exhaustion, potentially affecting all services on the host

🟠

Likely Case

Degraded performance or service crashes in applications using Mini-XML for XML processing

🟢

If Mitigated

Limited impact with proper memory monitoring and restart mechanisms in place

🌐 Internet-Facing: MEDIUM - Exploitable if XML parsing is exposed to untrusted input, but only causes DoS

🏢 Internal Only: LOW - Requires access to trigger XML parsing, limited to DoS impact

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Memory leak vulnerabilities typically require repeated triggering to cause noticeable impact

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check latest development code or version after October 2021

Vendor Advisory: https://github.com/michaelrsweet/mxml/issues/286

Restart Required: Yes

Instructions:

1. Check current Mini-XML version. 2. Update to latest version from official repository. 3. Recompile applications using the library. 4. Restart affected services.

🔧 Temporary Workarounds

Memory usage monitoring

all

Implement monitoring to detect abnormal memory consumption in processes using Mini-XML

Input validation

all

Validate and sanitize XML input before processing with Mini-XML library

🧯 If You Can't Patch

Implement rate limiting on XML processing endpoints
Deploy memory monitoring with automatic restart thresholds for affected processes

🔍 How to Verify

Check if Vulnerable:

Check if applications link to Mini-XML v3.2 library using ldd or equivalent dependency checking

Check Version:

mxml-config --version or check library files for version information

Verify Fix Applied:

Verify updated library version and test XML processing under load

📡 Detection & Monitoring

Log Indicators:

Abnormal memory consumption patterns
Process crashes or restarts
Out of memory errors in application logs

Network Indicators:

Increased XML processing requests
Service unavailability after XML processing

SIEM Query:

Process memory usage > threshold AND process name contains applications using XML parsing

📊 Metadata

CVE ID: CVE-2021-42859

CVSS v3 Score: 7.5 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-772

Published: May 26, 2022

Last Updated: November 21, 2024

🔗 References

https://github.com/michaelrsweet/mxml/issues/286 Exploit,Issue Tracking,Third Party Advisory
https://github.com/michaelrsweet/mxml/issues/286 Exploit,Issue Tracking,Third Party Advisory

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🔗 Related Vulnerabilities

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