VulnerabilityPublished 11 Nov 2026

CVE-2026-50256: xorg-x11-server-xwayland security update

Affects xorg-x11-server-xwaylandSource GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-50256· High 7.8

Not known to be exploited · CVSS 7.8 High : upgrade to xorg-x11-server-Xwayland-22.1.2-40.oe2403sp4 soon.

Data as of 11 Nov 2026, 13:20 UTC

CVSS 3.1 base score

7.8High

How severe the flaw is on the 0–10 CVSS scale.

Sources agree

CVSS scores by source
CNA (redhat)	CVSS 3.1	7.8
ADP (redhat-SADP)	CVSS 3.1	7.8

Patch: Available – fixed in xorg-x11-server-Xwayland-22.1.2-40.oe2403sp4

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade xorg-x11-server-xwayland to xorg-x11-server-Xwayland-22.1.2-40.oe2403sp4.

Affected software

Product	Affected	Fixed in
openEuler 24.03-LTS-SP4xorg-x11-server-xwayland`pkg:rpm/openEuler/xorg-x11-server-xwayland&distro=openEuler-24.03-LTS-SP4`Other threats	Affected <xorg-x11-server-Xwayland-22.1.2-40.oe2403sp4	Fixed in xorg-x11-server-Xwayland-22.1.2-40.oe2403sp4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

Xwayland is an X server for running X clients under Wayland. %package devel Summary: Development package Requires: pkgconfig %description devel The development package provides the developmental files which are necessary for developing Wayland compositors using Xwayland. %prep %autosetup -n xwayland- -p1 %build %meson \ -Ddefault_font_path=&quot;catalogue:/etc/X11/fontpath.d,built-ins&quot; \ -Dbuilder_string=&quot;Build ID: -&quot; \ -Dxkb_output_dir=/lib/xkb \ -Dxcsecurity=true \ -Dglamor=true \ -Ddri3=true %meson_build Security Fix(es): ['Hi all,\n\nCVEs have been issued now, please see inline below\n\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\nX.Org Security Advisory: June 2, 2026 \n\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\n=======================================================================\n\nMultiple issues have been found in the X server and Xwayland implementations\npublished by X.Org for which we are releasing security fixes for in\nxorg-server-21.1.23 and xwayland-24.1.12.\n\nNote that CVEs have been requested for these issues but did not get assigned in\ntime for this disclosure.\n\n* Font Alias Stack-based Buffer Overflow\n\n A mismatch between the X server and the libXfont2 library's maximum\n font name length can cause a stack buffer overflow during font alias\n resolution. The server allocates a 256 byte stack buffer but libXfont2's\n alias target name length is 1024 bytes. A font alias name between 257\n and 1023 bytes causes the X server to copy that name into the undersized\n stack buffer without further checks.\n\n Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\n Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\n (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\n\n A client that sets up multiple fence triggers can trigger a\n use-after-free function pointer call. An attacker would connect to the\n X server to set up a fence and await that fence, then a second X\n connection destroys the fence, causing the use-after-free.\n\n Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\n Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\n (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\n\n The X server has multiple stack buffers that are sized\n XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\n or clamp non-canonical key types to XkbMaxShiftLevel. A client can\n change key types to excessive shift levels and trigger three separate\n stack overflows.\n\n This is caused by an incomplete fix of CVE-2025-26597.\n\n Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\n Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\n (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\n\n _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\n indexed by key type index. The helper function CheckKeyTypes() writes\n to this buffer at a client-controlled offset, allowing a stack buffer\n overflow.\n\n Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\n Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\n (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\n\n A client that sets up multiple SyncCounters and awaits on those\n triggers can trigger a use-after-free when destroying those counters\n via a second client connection.\n\n Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\n Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\n (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\n\n A client that sets up multiple SyncCounters can trigger a use-after-free\n when destroying those counters via a second client connection while\n changing those counters.\n\n Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\n Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\n (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\n\n A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\n can read (or write) a client-contr(CVE-2026-50256)

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