Bug#1108073: xorg-server: Followup to CVE-2025-49176

[Salvatore Bonaccorso <carnil@debian.org>]

Source: xorg-server
Version: 2:21.1.16-1.2
Severity: grave
Tags: security upstream
Justification: user security hole
X-Debbugs-Cc: carnil@debian.org, Debian Security Team <team@security.debian.org>

As per

https://www.openwall.com/lists/oss-security/2025/06/18/2
https://gitlab.freedesktop.org/xorg/xserver/-/commit/4fc4d76b2c7aaed61ed2653f997783a3714c4fe1

there is another case where the BigRequest length can cause an
overflow, so an additional commit is required as followup to the fixes
for CVE-2025-49176.

Regards,
Salvatore