{"id":"CVE-2021-26957","aliases":["CVE-2021-26955","CVE-2021-26956","CVE-2021-26958","GHSA-2xpg-3hx4-fm9r","GHSA-3288-cwgw-ch86","GHSA-3cj3-jrrp-9rxf","GHSA-mp6r-fgw2-rxfx","RUSTSEC-2021-0019"],"url":"https://o3.security/vulnerability/CVE-2021-26957","summary":"Out of bounds read in xcb","details":"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.","published":"2021-02-09T23:15:14.023Z","modified":"2026-03-14T10:52:39.041025Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"crates.io","name":"xcb","fixedVersion":"1.0.0"}],"fix":null,"references":[{"type":"EVIDENCE","url":"https://rustsec.org/advisories/RUSTSEC-2021-0019.html"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-03-14T10:52:39.041025Z"}}