CyberRota Analysis
AI-GeneratedThe vulnerability arises in the libXfont2 font-server client, where insufficient validation allows a malicious font server to exploit a heap buffer overflow by sending overlapping source offsets. This can lead to arbitrary code execution due to the overflow of a destination buffer, posing a critical risk to systems utilizing this library. Organizations using libXfont2 should prioritize patching this vulnerability to mitigate potential exploitation.
Original NVD Description
fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. It does not check whether the running destination cursor has exceeded the allocation. A malicious font server can send overlapping source offsets -- for example 1000 glyphs each referencing {position:0, length:64} with nbytes=64. Each individual source range passes the existing validation, but the cumulative writes total 64000 bytes into a 64-byte destination buffer. This is a heap buffer overflow with attacker-controlled content.