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X.Org X Server CVE-2026-50263

| EUVD-2026-34820 MEDIUM
Use After Free (CWE-416)
2026-06-05 redhat GHSA-4ph5-83mw-vm42
Information Disclosure Use After Free Memory Corruption Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9
5.5
CVSS 3.1 · Vendor: redhat
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Severity by source

Vendor (redhat) PRIMARY
5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
SUSE
MEDIUM
qualitative
Red Hat
5.5 MEDIUM
qualitative

Primary rating from Vendor (redhat).

CVSS VectorVendor: redhat

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

2
Analysis Generated
Jun 05, 2026 - 12:20 vuln.today
CVE Published
Jun 05, 2026 - 10:36 nvd
MEDIUM 5.5

DescriptionCVE.org

A use-after-free flaw was found in the X.Org X server and Xwayland in CreateSaverWindow(). A client can trigger a use-after-free read after changing window attributes and forcing the screen saver, leading to information disclosure.

AnalysisAI

Use-after-free read in X.Org X server and Xwayland's CreateSaverWindow() function exposes heap memory to local authenticated users, resulting in information disclosure. A low-privileged local X client can manipulate window attributes and force screen saver activation to trigger a read from freed memory, leaking potentially sensitive heap contents (C:H/I:N/A:N). …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Gain low-privilege local shell access
Delivery
Open X client connection to running X server
Exploit
Manipulate window attributes via X11 protocol
Execution
Force screen saver activation via XActivateScreenSaver
Persist
Trigger use-after-free read in CreateSaverWindow()
Impact
Receive leaked heap memory contents
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Vulnerability AssessmentAI

Exploitation Exploitation requires a local account on the target system with the ability to open an X client connection to the running X server (AV:L/PR:L from CVSS vector). … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 3.1 vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N places this at Medium severity (5.5). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A low-privileged local user with shell access on a system running an X server opens an X client connection, programmatically alters window attributes on a targeted window, then issues a command to force screen saver activation. This sequence causes CreateSaverWindow() to read from a freed heap region, and the server returns or leaks the stale memory contents to the client - potentially including sensitive data resident in the X server's heap at the time of the free. …
Remediation The primary fix is the upstream commit ecc634f1b2f7aa473d3a267eada98c4918bf9e05 to the xorg/xserver repository on freedesktop.org GitLab; a tagged release version incorporating this fix is not independently confirmed from the provided data, so administrators should monitor the xorg-announce mailing list post at https://lists.x.org/archives/xorg-announce/2026-June/003702.html for an official release announcement. … Detailed patch versions, workarounds, and compensating controls in full report.
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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
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SUSE Linux Enterprise High Performance Computing 15 SP7 Affected
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CVE-2026-50263 vulnerability details – vuln.today
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