{"id":86483,"date":"2026-02-17T01:26:57","date_gmt":"2026-02-17T01:26:57","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T00:00:00","slug":"cve-2025-6021-critical-buffer-overflow-vulnerability-in-libxml2-s-xmlbuildqname-function","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-6021-critical-buffer-overflow-vulnerability-in-libxml2-s-xmlbuildqname-function\/","title":{"rendered":"CVE-2025-6021: Critical Buffer Overflow Vulnerability in libxml2’s xmlBuildQName function<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

The CVE-2025-6021 vulnerability represents a critical flaw in the libxml2’s xmlBuildQName function, with potential system-wide implications. This flaw can lead to both memory corruption and denial of service, thereby compromising the integrity of affected systems. Given the widespread use of libxml2 in parsing XML, this vulnerability could impact a wide range of software and applications, making its mitigation a priority for system administrators and developers.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-6021
\nSeverity: High (7.5 – CVSS score)
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Memory corruption, denial of service, potential system compromise, and data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

libxml2 | All versions prior to patch<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The exploit leverages an integer overflow in buffer size calculations within the xmlBuildQName function of libxml2. By inputting crafted data that triggers this overflow, an attacker can cause a stack-based buffer overflow. This results in memory corruption or a denial of service, thereby compromising the security and stability of the system.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

The following pseudocode represents a conceptual example of how this vulnerability may be exploited:<\/p>\n

import libxml2\ndef exploit_cve_2025_6021(target):\ncrafted_input = \"A\" * 2147483647  # Integer overflow\nlibxml2.xmlBuildQName(target, crafted_input)<\/code><\/pre>\n
In this example, the `crafted_input` is designed to trigger an integer overflow in the `xmlBuildQName` function, leading to a buffer overflow and subsequent system compromise.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview The CVE-2025-6021 vulnerability represents a critical flaw in the libxml2’s xmlBuildQName function, with potential system-wide implications. This flaw can lead to both memory corruption and denial of service, thereby compromising the integrity of affected systems. Given the widespread use of libxml2 in parsing XML, this vulnerability could impact a wide range of software and […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-86483","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t