OESA-2026-1292

GLib is a bundle of three (formerly five) low-level system libraries written in C and developed mainly by GNOME. GLib's code was separated from GTK, so it can be used by software other than GNOME and has been developed in parallel ever since.

Security Fix(es):

Integer Overflow vulnerability in the gbufferedinputstreampeek() function of the GLib library. The issue is caused by missing validation of the offset and count parameters, leading to an unsafe arithmetic operation during length calculation. When specially crafted values are provided, the offset + count computation may overflow, resulting in an incorrect size being passed to memcpy(). This can trigger a heap or stack buffer overflow and lead to a segmentation fault. Exploitation is subject to strict preconditions and primarily impacts availability by causing application crashes.(CVE-2026-0988)

A flaw was found in the GLib Base64 encoding routine when processing very large input data. Due to incorrect use of integer types during length calculation, the library may miscalculate buffer boundaries. This can cause memory writes outside the allocated buffer. Applications that process untrusted or extremely large Base64 input using GLib may crash or behave unpredictably.(CVE-2026-1484)

A flaw was found in Glib's content type parsing logic. This buffer underflow vulnerability occurs because the length of a header line is stored in a signed integer, which can lead to integer wraparound for very large inputs. This results in pointer underflow and out-of-bounds memory access. Exploitation requires a local user to install or process a specially crafted treemagic file, which can lead to local denial of service or application instability.(CVE-2026-1485)