CVE-2007-4990: X.org X Font Server

High severity, CVSS 7.5. EPSS: 10.7% chance of exploitation in the next 30 days.

The swap_char2b function in X.Org X Font Server (xfs) before 1.0.5 allows context-dependent attackers to execute arbitrary code via (1) QueryXBitmaps and (2) QueryXExtents protocol requests with crafted size values that specify an arbitrary number of bytes to be swapped on the heap, which triggers heap corruption.

Affected products

• X.org X Font Server: up to and including 1.0.4

Published 2007-10-05. Last modified 2026-06-16.