This security update addresses multiple vulnerabilities in TigerVNC for RHEL 6 ELS, including high-severity flaws (CVE-2026-33999 & CVE-2026-34001, CVSS 7.8) such as use-after-free and integer underflow in X.Org X server components, which can lead to denial of service, memory corruption, and information disclosure. The affected versions are Red Hat Enterprise Linux 6.0, 7.0, 8.0, and 9.0, as per NVD data. Red Hat has rated this update as Important; administrators should apply the provided patches immediately.
Red Hat Product Errata RHSA-2026:23496 - Security Advisory Issued: 2026-06-04 Updated: 2026-06-04 RHSA-2026:23496 - Security Advisory Overview Updated Packages Synopsis Important: tigervnc security update Type/Severity Security Advisory: Important Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for tigervnc is now available for Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. Description Virtual Network Computing (VNC) is a remote display system which allows users to view a computing desktop environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures. TigerVNC is a suite of VNC servers and clients. Security Fix(es): xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling (CVE-2026-33999) xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in XKB geometry processing. (CVE-2026-34000) xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption (CVE-2026-34001) xorg: xwayland: X.Org X server: Information disclosure or Denial of Service via out-of-bounds read in XKB modifier map handling (CVE-2026-34002) xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory access (CVE-2026-34003) TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of service via incorrect permissions (CVE-2026-34352) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section. Solution For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Affected Products Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64 Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386 Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x Fixes BZ - 2451106 - CVE-2026-33999 xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling BZ - 2451107 - CVE-2026-34000 xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in XKB geometry processing. BZ - 2451109 - CVE-2026-34001 xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption BZ - 2451112 - CVE-2026-34002 xorg: xwayland: X.Org X server: Information disclosure or Denial of Service via out-of-bounds read in XKB modifier map handling BZ - 2451113 - CVE-2026-34003 xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory access BZ - 2452022 - CVE-2026-34352 TigerVNC: x0vncserver: TigerVNC x0vncserver: Information disclosure, data manipulation, and denial of service via incorrect permissions CVEs CVE-2026-33999 CVE-2026-34000 CVE-2026-34001 CVE-2026-34002 CVE-2026-34003 CVE-2026-34352 References https://access.redhat.com/security/updates/classification/#important Note: More recent versions of these packages may be available. Click a package name for more details. Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 SRPM tigervnc-1.1.0-25.el6_10.16.src.rpm SHA-256: bf60b41824d6c75dd5654d6dfbbd00792cbbe5b7e451d99046bcf1ed6b490aa4 x86_64 tigervnc-1.1.0-25.el6_10.16.x86_64.rpm SHA-256: 4a1556ab3f4b5410fd5d1435ebe86973d9e0b1bd60f292bdd23dd715f85a878d tigervnc-debuginfo-1.1.0-25.el6_10.16.x86_64.rpm SHA-256: 5839a1985a962d480705baf153a8d5d096310eb3f2e5adf642f5e04c0d4757d9 tigervnc-debuginfo-1.1.0-25.el6_10.16.x86_64.rpm SHA-256: 5839a1985a962d480705baf153a8d5d096310eb3f2e5adf642f5e04c0d4757d9 tigervnc-server-1.1.0-25.el6_10.16.x86_64.rpm SHA-256: 18fc9624513e99ae3d3d2a858dd8d15b781ef1aa7e0e149de182ba3c665e5e17 tigervnc-server-applet-1.1.0-25.el6_10.16.noarch.rpm SHA-256: b052e9cf815dcd5d5455020614fa61a6a6893ddd009220508b750d44d5a616f7 tigervnc-server-module-1.1.0-25.el6_10.16.x86_64.rpm SHA-256: f0f1c0df41fba3ed9b3f8c848b6925a9b67cc85f6a4931ff96c9798b0f7019e4 i386 tigervnc-1.1.0-25.el6_10.16.i686.rpm SHA-256: daa47460d29469e31536fc6a0ff1444c154895a0b19b2aedffa1e679fd963b52 tigervnc-debuginfo-1.1.0-25.el6_10.16.i686.rpm SHA-256: 3bbb782a090c214007931374773ff9891aa05ab9b9492e4a7b08886730b0ce27 tigervnc-debuginfo-1.1.0-25.el6_10.16.i686.rpm SHA-256: 3bbb782a090c214007931374773ff9891aa05ab9b9492e4a7b08886730b0ce27 tigervnc-server-1.1.0-25.el6_10.16.i686.rpm SHA-256: b64cad186db57a3b70fd813a92cb2e54508a74690021556d09e0a0e3ad8c72b7 tigervnc-server-applet-1.1.0-25.el6_10.16.noarch.rpm SHA-256: b052e9cf815dcd5d5455020614fa61a6a6893ddd009220508b750d44d5a616f7 tigervnc-server-module-1.1.0-25.el6_10.16.i686.rpm SHA-256: 6fa37341a1fcd0fe5f4a125e5be31405176af9df4cf57949755e2fc13a3211cb Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 SRPM tigervnc-1.1.0-25.el6_10.16.src.rpm SHA-256: bf60b41824d6c75dd5654d6dfbbd00792cbbe5b7e451d99046bcf1ed6b490aa4 s390x tigervnc-1.1.0-25.el6_10.16.s390x.rpm SHA-256: 81e2d2ef02914f2cd3e91932cce3943be8762210fb5c861925e6e128cde6242d tigervnc-debuginfo-1.1.0-25.el6_10.16.s390x.rpm SHA-256: ef48e23416c4c521b66202ff05e3ce8ebe835c5d253b44bb75cc428a40a54265 tigervnc-server-1.1.0-25.el6_10.16.s390x.rpm SHA-256: 8896e508a8183ac72e50e9b004d4f6b746a30ace731411da5fe351af2797ba47 tigervnc-server-applet-1.1.0-25.el6_10.16.noarch.rpm SHA-256: b052e9cf815dcd5d5455020614fa61a6a6893ddd009220508b750d44d5a616f7 The Red Hat security contact is secalert@redhat.com . More contact details at https://access.redhat.com/security/team/contact/ .