CVE-2021-26957: Xcb Project Xcb

Critical severity, CVSS 9.8. EPSS: 1.7% chance of exploitation in the next 30 days.

An issue was discovered in the xcb crate through 2021-02-04 for Rust. It has a soundness violation because there is an out-of-bounds read in xcb::xproto::change_property(), as demonstrated by a format=32 T=u8 situation where out-of-bounds bytes are sent to an X server.

Affected products

• Xcb Project Xcb: up to and including 2021-02-04

Published 2021-02-09. Last modified 2026-06-17.