CVE-2025-6052 in glib
Summary
by MITRE • 06/13/2025
A flaw was found in how GLib’s GString manages memory when adding data to strings. If a string is already very large, combining it with more input can cause a hidden overflow in the size calculation. This makes the system think it has enough memory when it doesn’t. As a result, data may be written past the end of the allocated memory, leading to crashes or memory corruption.
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Analysis
by VulDB Data Team • 02/03/2026
The vulnerability identified as CVE-2025-6052 resides within GLib's GString implementation, a fundamental component of the GLib library that provides core data types and utility functions for applications built on the glib-2.0 framework. This flaw represents a critical memory safety issue that affects how the library handles string concatenation operations when dealing with already large string objects. The vulnerability manifests when a GString instance that has grown to substantial size undergoes further concatenation operations with additional input data, creating a scenario where internal size calculations become compromised.
The technical root cause of this vulnerability stems from an insufficient overflow check during size calculation within the GString memory management system. When a large GString is being extended with new data, the library performs internal arithmetic to determine the required memory allocation for the combined result. However, the calculation logic fails to properly validate whether the resulting size would exceed the maximum representable value for the data type used in size tracking. This oversight creates a scenario where the system believes sufficient memory exists for the operation, when in reality the allocated memory space is insufficient to accommodate the actual data being written.
The operational impact of CVE-2025-6052 extends beyond simple program crashes, as the vulnerability presents significant security risks through potential memory corruption. When the system writes data past the end of allocated memory boundaries, it can overwrite adjacent memory regions, potentially corrupting other data structures or executable code. This memory corruption can lead to unpredictable program behavior, application crashes, or in more severe cases, allow attackers to execute arbitrary code through carefully crafted input sequences. The vulnerability affects any application that relies on GLib's GString functionality, including desktop applications, server software, and system utilities built using the glib-2.0 library ecosystem.
This vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and represents a variant of the broader class of memory safety issues that fall under the ATT&CK technique T1059.007 for command and scripting interpreter. The flaw demonstrates how seemingly benign string manipulation operations can become attack vectors when memory management calculations are not properly validated. The risk is particularly elevated in environments where applications process untrusted input data through GString operations, as attackers could exploit the vulnerability to craft inputs that trigger the overflow condition. Mitigation efforts should focus on updating to patched versions of GLib, implementing additional input validation layers, and considering memory safety enhancements such as address sanitization tools during development and testing phases. Organizations should prioritize this vulnerability as it affects a widely-used foundational library that underpins numerous applications across multiple operating systems and software distributions.