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CVE Record

CVE-2026-34003: Xorg: xwayland: x.org x server: information exposure and denial of service via out-of-bounds memory access

A flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This could result in the disclosure of sensitive information or cause the server to crash, leading to a Denial of Service (DoS). In certain configurations, higher impact outcomes may be possible.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-34003 is a high-severity flaw in X.Org X server request handling. A local attacker could make the graphical server read memory outside expected bounds, potentially exposing sensitive information or crashing the session. The source bundle names affected Red Hat Enterprise Linux packages, including Xwayland, xorg-x11-server, and TigerVNC.

Executive priority

Treat this as a high-priority Linux endpoint and server maintenance issue, especially for shared graphical systems. It is not evidenced as internet-exploited, but local compromise could expose data or disrupt critical operator sessions.

Technical view

The flaw is in XKB key types request validation and is classified as CWE-125. The CVSS 3.1 score is 7.8 with local attack vector, low complexity, low privileges, no user interaction, and high confidentiality, integrity, and availability impact. Red Hat advisories are listed, but the bundle does not provide fixed package versions.

Likely exposure

Exposure is most likely on affected Red Hat Enterprise Linux 6 ELS, 7 ELS, 8, 8.x extended support streams, and 10 systems running the listed Xwayland, xorg-x11-server, or TigerVNC packages.

Exploitation context

The provided bundle does not support active exploitation, and KEV status is false. Exploitation requires local access and the ability to send a crafted request to the X server. Remote exposure is not established by the sources.

Researcher notes

The key uncertainty is remediation detail: the bundle lists many Red Hat advisories but not fixed package versions. Analysis should remain scoped to Red Hat-listed packages and local X server request handling unless additional vendor data broadens affected products.

Mitigation direction

  • Review the applicable Red Hat RHSA advisory for each affected RHEL stream.
  • Apply vendor-provided updates for affected Xwayland, xorg-x11-server, or TigerVNC packages.
  • Prioritize multi-user desktops, VNC hosts, jump boxes, and shared Linux workstations.
  • Restrict local shell and graphical-session access to trusted users.
  • Check vendor guidance before applying compensating controls not named in the advisories.

Validation and detection

  • Inventory systems for the affected Red Hat products and package names.
  • Compare installed package versions against the relevant Red Hat advisory.
  • Confirm whether X.Org, Xwayland, or TigerVNC is installed and in use.
  • Verify update deployment through package management and vulnerability scanner results.
  • Review local access controls for shared graphical or VNC environments.
Prepared
Confidence
high
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-125: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-34003 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
7Timeline events
2ADP providers
39Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9redhat
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2026-34003Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Reported to Red Hat.

  3. Source timelineredhat

    Reported to Red Hat.

  4. ADP timelineredhat-SADP

    Made public.

  5. Source timelineredhat

    Made public.

  6. CVE publishedCVE Program

    The CVE record was published.

  7. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPxorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory access
other:Red Hat severity ratingcvssV3_1
  • 2026-03-25T07:19:13.949Z: Reported to Red Hat.
  • 2026-04-23T14:18:00.653Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Red HatRed Hat Enterprise Linux 10xorg-x11-server-Xwayland, 0:24.1.5-6.el10_1affected
Red HatRed Hat Enterprise Linux 10xorg-x11-server-Xwayland, 0:24.1.9-4.el10_2affected
Red HatRed Hat Enterprise Linux 10.0 Extended Update Supportxorg-x11-server-Xwayland, 0:24.1.5-6.el10_0affected
Red HatRed Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONtigervnc, 0:1.1.0-25.el6_10.16affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supportxorg-x11-server, 0:1.20.4-34.el7_9affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supporttigervnc, 0:1.8.0-36.el7_9.4affected
Red HatRed Hat Enterprise Linux 8xorg-x11-server-Xwayland, 0:21.1.3-20.el8_10affected
Red HatRed Hat Enterprise Linux 8xorg-x11-server, 0:1.20.11-28.el8_10affected
Red HatRed Hat Enterprise Linux 8tigervnc, 0:1.15.0-9.el8_10affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportxorg-x11-server, 0:1.20.10-4.el8_4affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supporttigervnc, 0:1.11.0-8.el8_4.15affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Onxorg-x11-server, 0:1.20.10-4.el8_4affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Ontigervnc, 0:1.11.0-8.el8_4.15affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportxorg-x11-server-Xwayland, 0:21.1.3-2.el8_6.6affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportxorg-x11-server, 0:1.20.11-7.el8_6affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supporttigervnc, 0:1.12.0-6.el8_6.17affected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-Ontigervnc, 0:1.12.0-6.el8_6.17affected
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update Servicexorg-x11-server-Xwayland, 0:21.1.3-2.el8_6.6affected
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update Servicexorg-x11-server, 0:1.20.11-7.el8_6affected
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP Solutionsxorg-x11-server-Xwayland, 0:21.1.3-2.el8_6.6affected
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP Solutionsxorg-x11-server, 0:1.20.11-7.el8_6affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicexorg-x11-server-Xwayland, 0:21.1.3-13.el8_8affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicexorg-x11-server, 0:1.20.11-18.el8_8affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicetigervnc, 0:1.12.0-15.el8_8.17affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionsxorg-x11-server-Xwayland, 0:21.1.3-13.el8_8affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionsxorg-x11-server, 0:1.20.11-18.el8_8affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionstigervnc, 0:1.12.0-15.el8_8.17affected
Red HatRed Hat Enterprise Linux 9tigervnc, 0:1.15.0-6.el9_7.1affected
Red HatRed Hat Enterprise Linux 9xorg-x11-server-Xwayland, 0:23.2.7-6.el9_7affected
Red HatRed Hat Enterprise Linux 9xorg-x11-server, 0:1.20.11-33.el9_7affected
Weakness

CWE details

CWE-125

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-125 · source CWE mapping

Out-of-bounds Read

Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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