{"id":"CVE-2025-26596","title":"A heap overflow flaw was found in X.Org and Xwayland","summary":"A heap overflow flaw was found in X.Org and Xwayland. The computation of the length in XkbSizeKeySyms() differs from what is written in XkbWriteKeySyms(), which may lead to a heap-based buffer overflow.","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-787","CWE-787"],"vendor":"tigervnc","product":"tigervnc","affected":["tigervnc","x_server < 21.1.16","xwayland < 24.1.6","enterprise_linux = 7.0","enterprise_linux = 8.0","enterprise_linux = 9.0"],"patched":["x_server 21.1.16","xwayland 24.1.6"],"published":"2025-02-25","updated":"2026-06-25","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-26596","references":[{"url":"https://access.redhat.com/errata/RHSA-2025:2500","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2502","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2861","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2862","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2865","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2866","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2873","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2874","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2875","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2879","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:2880","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:3976","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:7163","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:7165","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2025:7458","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/security/cve/CVE-2025-26596","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2345256","label":"secalert@redhat.com"},{"url":"https://lists.debian.org/debian-lts-announce/2025/02/msg00036.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.00438,"epssPercentile":0.37498,"ingestedAt":"2026-06-29T13:24:34.167Z","slug":"CVE-2025-26596","body":"## Overview\n\nA heap overflow flaw was found in X.Org and Xwayland. The computation of the length in XkbSizeKeySyms() differs from what is written in XkbWriteKeySyms(), which may lead to a heap-based buffer overflow.\n\n## Affected\n\n- `tigervnc`\n- `x_server < 21.1.16`\n- `xwayland < 24.1.6`\n- `enterprise_linux = 7.0`\n- `enterprise_linux = 8.0`\n- `enterprise_linux = 9.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `x_server 21.1.16`\n- `xwayland 24.1.6`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}