Red Hat Security Advisory: tigervnc security update

Fixed packages 5

Vulnerabilities 8

• High 7.8
  CVE-2025-26594

  X.org: xwayland: use-after-free of the root cursor

  A use-after-free flaw was found in X.Org and Xwayland. The root cursor is referenced in the X server as a global variable. If a client frees the root cursor, the internal reference points to freed memory and causes a use-after-free.

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Feb 25, 2025
• High 7.8
  CVE-2025-26595

  Xorg: xwayland: buffer overflow in xkbvmodmasktext()

  A buffer overflow flaw was found in X.Org and Xwayland. The code in XkbVModMaskText() allocates a fixed-sized buffer on the stack and copies the names of the virtual modifiers to that buffer. The code fails to check the bounds of the buffer and would copy the…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Feb 25, 2025
• High 7.8
  CVE-2025-26596

  Xorg: xwayland: heap overflow in xkbwritekeysyms()

  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.

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux
  Feb 25, 2025
• High 7.8
  CVE-2025-26597

  Xorg: xwayland: buffer overflow in xkbchangetypesofkey()

  A buffer overflow flaw was found in X.Org and Xwayland. If XkbChangeTypesOfKey() is called with a 0 group, it will resize the key symbols table to 0 but leave the key actions unchanged. If the same function is later called with a non-zero value of groups, thi…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Feb 25, 2025
• High 7.8
  CVE-2025-26598

  Xorg: xwayland: out-of-bounds write in createpointerbarrierclient()

  An out-of-bounds write flaw was found in X.Org and Xwayland. The function GetBarrierDevice() searches for the pointer device based on its device ID and returns the matching value, or supposedly NULL, if no match was found. However, the code will return the la…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Feb 25, 2025
• High 7.8
  CVE-2025-26599

  Xorg: xwayland: use of uninitialized pointer in compredirectwindow()

  An access to an uninitialized pointer flaw was found in X.Org and Xwayland. The function compCheckRedirect() may fail if it cannot allocate the backing pixmap. In that case, compRedirectWindow() will return a BadAlloc error without validating the window tree …

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Feb 25, 2025
• High 7.8
  CVE-2025-26600

  Xorg: xwayland: use-after-free in playreleasedevents()

  A use-after-free flaw was found in X.Org and Xwayland. When a device is removed while still frozen, the events queued for that device remain while the device is freed. Replaying the events will cause a use-after-free.

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Feb 25, 2025
• High 7.8
  CVE-2025-26601

  Xorg: xwayland: use-after-free in syncinittrigger()

  A use-after-free flaw was found in X.Org and Xwayland. When changing an alarm, the values of the change mask are evaluated one after the other, changing the trigger values as requested, and eventually, SyncInitTrigger() is called. If one of the changes trigge…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Feb 25, 2025

References

• article
  https://access.redhat.com/security/updates/classification/#important
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345248
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345251
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345252
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345253
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345254
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345255
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345256
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2345257
• advisory
  https://security.access.redhat.com/data/csaf/v2/advisories/2025/rhsa-2025_3976.json
• report
  https://access.redhat.com/security/cve/CVE-2025-26594
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26594
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26594
• report
  https://access.redhat.com/security/cve/CVE-2025-26595
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26595
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26595
• report
  https://access.redhat.com/security/cve/CVE-2025-26596
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26596
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26596
• report
  https://access.redhat.com/security/cve/CVE-2025-26597
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26597
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26597
• report
  https://access.redhat.com/security/cve/CVE-2025-26598
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26598
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26598
• report
  https://access.redhat.com/security/cve/CVE-2025-26599
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26599
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26599
• report
  https://access.redhat.com/security/cve/CVE-2025-26600
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26600
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26600
• report
  https://access.redhat.com/security/cve/CVE-2025-26601
• advisory
  https://www.cve.org/CVERecord?id=CVE-2025-26601
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2025-26601