Executive brief
GLib, a fundamental software library used by many Linux applications and Siemens industrial devices, contains a memory management flaw. An attacker could potentially cause a system crash or memory corruption by providing extremely large amounts of data to an application that uses this library. While difficult to exploit in practice due to the massive amount of memory required, it poses a risk to service availability and system stability.
Technical details
An integer overflow vulnerability exists in the g_string_maybe_expand() function of the GLib library. When an application appends data to an already extremely large GString, an internal size calculation can wrap around (integer overflow), leading the library to incorrectly assume sufficient buffer space exists. This results in a heap-based buffer overflow when the data is written. While the vulnerability requires specific conditions involving very large memory allocations, it can be triggered remotely if an application accepts untrusted input and processes it using GString. The issue is fixed in GLib versions 2.84.3 and 2.85.1.
Affected products
- GNOME GLib 2.75.3 up to 2.84.3
- Siemens SIMATIC CN 4100 All versions < V5.0
- Siemens RUGGEDCOM RST2428P All versions < V4.0
Timeline
- 2025-06-13: disclosed: Initial disclosure by Red Hat
- 2025-06-13: advisory: NVD published date
- 2026-05-12: advisory: Siemens published advisory SSA-032379 for SIMATIC CN 4100
- 2026-06-02: advisory: Siemens published advisory SSA-253495 for SINEC OS / RUGGEDCOM RST2428P