CVE-2018-16428 in glib
Summary
by MITRE
In GNOME GLib 2.56.1, g_markup_parse_context_end_parse() in gmarkup.c has a NULL pointer dereference.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability identified as CVE-2018-16428 represents a critical null pointer dereference flaw within the GNOME GLib library version 2.56.1. This issue specifically affects the g_markup_parse_context_end_parse() function located in the gmarkup.c source file, which serves as a core component for XML and markup parsing operations within the GLib library ecosystem. The vulnerability arises when the function processes malformed or improperly structured markup data, creating conditions where a null pointer reference can occur during the parsing termination phase.
The technical exploitation of this vulnerability stems from inadequate input validation and error handling within the markup parsing context. When g_markup_parse_context_end_parse() encounters certain malformed XML or markup sequences, it fails to properly initialize or validate pointer references before attempting to dereference them. This condition creates a scenario where the application crashes with a segmentation fault, effectively causing a denial of service condition. The flaw is particularly concerning because GLib serves as a fundamental library for numerous GNOME applications and other software projects that rely on its parsing capabilities, making the impact of this vulnerability widespread across the ecosystem.
From an operational perspective, this vulnerability presents significant risks to systems utilizing GNOME GLib 2.56.1, as attackers could potentially trigger the null pointer dereference through carefully crafted malicious markup data. The impact extends beyond simple application crashes, as this flaw can be leveraged in broader attack scenarios where malformed data is processed through applications that depend on GLib for parsing operations. The vulnerability aligns with CWE-476, which specifically addresses NULL pointer dereference conditions, and can be mapped to ATT&CK technique T1203, representing the exploitation of software vulnerabilities to achieve system compromise. Organizations running applications that utilize GLib for parsing markup content face potential service disruption and could be vulnerable to more sophisticated attacks if the vulnerability is not properly addressed.
Mitigation strategies for this vulnerability require immediate patching of affected systems to upgrade to GLib versions that contain the fix for this null pointer dereference issue. System administrators should prioritize updating their GNOME GLib installations to versions 2.56.2 or later, where the vulnerability has been resolved through proper pointer validation and initialization routines. Additionally, implementing input validation measures and sanitization of all markup data processed through GLib functions can provide defense-in-depth protection against exploitation attempts. Organizations should also consider monitoring for unusual application crashes or segmentation faults that might indicate exploitation attempts and maintain updated threat intelligence to identify potential attack vectors targeting this specific vulnerability class.