alsa-2026:26709
Vulnerability from osv_almalinux
Published
2026-06-17 00:00
Modified
2026-06-18 08:54
Summary
Important: xorg-x11-server security, bug fix, and enhancement update
Details

X.Org is an open-source implementation of the X Window System. It provides the basic low-level functionality that full-fledged graphical user interfaces are designed upon.

Security Fix(es):

  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch (CVE-2026-50256)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in miSyncDestroyFence() (CVE-2026-50257)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due to unchecked shift levels (CVE-2026-50258)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request via mapWidths indexing (CVE-2026-50259)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in FreeCounter() (CVE-2026-50260)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter() (CVE-2026-50261)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX ChangeDrawableAttributes (CVE-2026-50262)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free information disclosure in CreateSaverWindow() (CVE-2026-50263)
  • xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds heap write in DRI2 DRIGetBuffers/DRIGetBuffersWithFormat (CVE-2026-50264)

Bug Fix(es) and Enhancement(s):

  • [xserver] Backport other security fixes without a CVE assigned [almalinux-8.10.z] (JIRA:AlmaLinux-184289)

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.

References
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-Xdmx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-Xephyr"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-Xnest"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-Xorg"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-Xvfb"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-common"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-devel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "xorg-x11-server-source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.20.11-28.el8_10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "X.Org is an open-source implementation of the X Window System. It provides the basic low-level functionality that full-fledged graphical user interfaces are designed upon.  \n\nSecurity Fix(es):  \n\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch (CVE-2026-50256)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in miSyncDestroyFence() (CVE-2026-50257)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due to unchecked shift levels (CVE-2026-50258)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request via mapWidths indexing (CVE-2026-50259)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in FreeCounter() (CVE-2026-50260)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter() (CVE-2026-50261)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX ChangeDrawableAttributes (CVE-2026-50262)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free information disclosure in CreateSaverWindow() (CVE-2026-50263)\n  * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds heap write in DRI2 DRIGetBuffers/DRIGetBuffersWithFormat (CVE-2026-50264)\n\n\nBug Fix(es) and Enhancement(s):  \n\n  * [xserver] Backport other security fixes without a CVE assigned [almalinux-8.10.z] (JIRA:AlmaLinux-184289)\n\n\nFor 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.\n",
  "id": "ALSA-2026:26709",
  "modified": "2026-06-18T08:54:21Z",
  "published": "2026-06-17T00:00:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:26709"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50256"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50257"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50258"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50259"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50260"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50261"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50262"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50263"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-50264"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485380"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485382"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485383"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485384"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485385"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485386"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485387"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485388"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2485389"
    },
    {
      "type": "ADVISORY",
      "url": "https://errata.almalinux.org/8/ALSA-2026-26709.html"
    }
  ],
  "related": [
    "CVE-2026-50256",
    "CVE-2026-50257",
    "CVE-2026-50258",
    "CVE-2026-50259",
    "CVE-2026-50260",
    "CVE-2026-50261",
    "CVE-2026-50262",
    "CVE-2026-50263",
    "CVE-2026-50264"
  ],
  "summary": "Important: xorg-x11-server security, bug fix, and enhancement update"
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.