CVE-2025-6170: Red Hat JBoss Core Services DOS Vulnerability

CVE-2025-6170 Overview

A stack-based buffer overflow vulnerability (CWE-121) was discovered in the interactive shell component of xmllint, a command-line utility included with the libxml2 library for parsing XML files. When a user inputs an overly long command in the interactive shell, the program fails to properly validate the input size, leading to a stack buffer overflow condition. While the immediate impact is typically a denial of service through application crash, this vulnerability could potentially allow attackers to execute arbitrary code in rare configurations that lack modern memory protection mechanisms such as ASLR and stack canaries.

Critical Impact

Stack-based buffer overflow in xmllint interactive shell may cause denial of service and, in rare configurations without modern protections, could enable code execution.

Affected Products

• xmlsoft libxml2
• Red Hat Enterprise Linux 6.0, 7.0, 8.0, 9.0, 10.0
• Red Hat JBoss Core Services
• Red Hat OpenShift Container Platform 4.0

Discovery Timeline

• 2025-06-16 - CVE-2025-6170 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-6170

Vulnerability Analysis

This vulnerability resides in the interactive shell functionality of the xmllint utility. The xmllint tool is commonly used for parsing, validating, and transforming XML documents from the command line. When operating in interactive mode, the shell accepts user commands for processing XML data. The flaw occurs because the input handling routine does not properly validate the length of user-supplied commands before copying them into a fixed-size stack buffer.

The root cause is a classic stack-based buffer overflow (CWE-121) where the absence of proper bounds checking allows an attacker to overwrite adjacent stack memory. While exploitation requires local access and user interaction, the vulnerability presents a risk particularly on legacy systems or embedded environments that may not have modern exploit mitigations enabled.

Root Cause

The vulnerability stems from improper input validation in the xmllint interactive shell's command processing logic. When handling user input, the application allocates a fixed-size buffer on the stack but does not enforce length limits on the incoming command string. This allows an attacker to craft an excessively long command that exceeds the buffer's capacity, resulting in stack memory corruption.

Attack Vector

Exploitation requires local access to a system where xmllint is installed and running in interactive mode. An attacker must craft a malicious input string that exceeds the buffer size limits. The attack scenario involves:

1. Launching xmllint in interactive shell mode
2. Providing an excessively long command string that overflows the stack buffer
3. Overwriting adjacent stack memory including potentially the return address
4. In environments without stack canaries or ASLR, this could redirect execution flow

The vulnerability requires user interaction as the victim must be running xmllint in interactive mode. On modern systems with stack protection mechanisms, the most likely outcome is an application crash resulting in denial of service.

Detection Methods for CVE-2025-6170

Indicators of Compromise

• Unexpected crashes or segmentation faults in xmllint processes during interactive sessions
• Core dumps associated with xmllint containing evidence of stack corruption
• Unusual command history entries containing excessively long strings in xmllint interactive shell
• System logs indicating xmllint process terminations with memory violation signals

Detection Strategies

• Monitor for abnormal termination of xmllint processes, particularly those running in interactive mode
• Implement process monitoring to detect xmllint instances receiving unusually large input strings
• Use endpoint detection to identify stack buffer overflow attack patterns targeting xmllint
• Deploy file integrity monitoring on libxml2 library files to detect unauthorized modifications

Monitoring Recommendations

• Enable crash reporting and analyze core dumps from xmllint processes for signs of exploitation
• Audit usage of xmllint interactive mode across enterprise environments
• Monitor system logs for repeated xmllint crashes that may indicate exploitation attempts
• Implement application whitelisting to control which users can execute xmllint in interactive mode

How to Mitigate CVE-2025-6170

Immediate Actions Required

• Review and apply available security patches from Red Hat and your Linux distribution
• Restrict access to the xmllint utility to only trusted users who require it
• Consider disabling interactive shell mode if not operationally required
• Ensure modern exploit mitigations (ASLR, stack canaries) are enabled on systems running xmllint

Patch Information

Red Hat has acknowledged this vulnerability and is tracking it through their security advisory system. Administrators should consult the Red Hat CVE Advisory for the latest patch status and remediation guidance. Additional details are available in Red Hat Bug Report #2372952. Debian users should review the Debian LTS Announcement for applicable updates.

Workarounds

• Avoid using xmllint in interactive shell mode when processing untrusted or user-controlled input
• Run xmllint processes in sandboxed or containerized environments to limit potential impact
• Apply restrictive permissions to limit which users can access the xmllint binary
• Consider using alternative XML parsing tools that do not have an interactive shell component for sensitive operations

# Restrict xmllint access to authorized users only
chmod 750 /usr/bin/xmllint
chown root:xml-users /usr/bin/xmllint

# Verify stack protection is enabled on the system
cat /proc/sys/kernel/randomize_va_space
# Should return 2 for full ASLR protection