CVE-2025-6170 in libxml2
Summary
by MITRE • 06/16/2025
A flaw was found in the interactive shell of the xmllint command-line tool, used for parsing XML files. When a user inputs an overly long command, the program does not check the input size properly, which can cause it to crash. This issue might allow attackers to run harmful code in rare configurations without modern protections.
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Analysis
by VulDB Data Team • 04/20/2026
The vulnerability identified as CVE-2025-6170 resides within the xmllint command-line tool's interactive shell implementation, representing a classic buffer overflow condition that manifests through improper input validation. This flaw specifically targets the command-line interface's handling of user input during interactive sessions, where the application fails to enforce adequate size limitations on command line arguments. The vulnerability operates at the boundary between user-supplied data and the application's internal memory management, creating a potential entry point for malicious actors to exploit the tool's memory handling mechanisms.
The technical implementation of this vulnerability stems from inadequate input sanitization within the xmllint interactive shell component, where the program processes user commands without proper bounds checking on input length. When an attacker provides an excessively long command string, the application's memory allocation routines fail to validate the input size, leading to memory corruption that results in program termination or potentially arbitrary code execution. This weakness aligns with CWE-122, which describes heap-based buffer overflow conditions, and demonstrates how improper input validation can lead to memory corruption vulnerabilities. The vulnerability's exploitation potential is heightened in environments where modern exploit mitigation techniques such as stack canaries, address space layout randomization, and non-executable stack protections are disabled or bypassed.
The operational impact of CVE-2025-6170 extends beyond simple denial-of-service scenarios, as the vulnerability can potentially enable remote code execution under specific conditions. Attackers may leverage this weakness to craft malicious input sequences that trigger memory corruption, potentially leading to arbitrary code execution with the privileges of the user running the xmllint tool. The risk assessment is particularly concerning in environments where xmllint is used interactively with untrusted input or where the tool operates in automated contexts that process XML content from external sources. This vulnerability directly relates to ATT&CK technique T1203, which involves legitimate user execution, and T1059, covering command and scripting interpreter usage, as it exploits the tool's interactive shell functionality to execute malicious commands.
Mitigation strategies for CVE-2025-6170 should prioritize immediate patching of affected versions of libxml2, which contains the xmllint tool implementation. System administrators should implement input validation controls at the application level, enforcing maximum command length limits and implementing proper buffer management techniques to prevent overflow conditions. Additional protective measures include deploying application whitelisting policies that restrict execution of xmllint in interactive modes, implementing network segmentation to limit exposure of systems running vulnerable versions, and establishing monitoring protocols to detect unusual command execution patterns. Organizations should also consider disabling interactive shell functionality for xmllint in production environments and implementing automated input sanitization processes that validate XML content before processing. The remediation approach must align with security best practices outlined in NIST SP 800-144 and ISO/IEC 27001 standards, emphasizing the importance of input validation and secure coding practices in preventing buffer overflow vulnerabilities.