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CVE Record

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 marked just before, which leaves the validated data partly initialized and the use of an uninitialized pointer later.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a local vulnerability in X.Org/Xwayland-related graphics components. A logged-in local user could trigger a memory-handling flaw that may affect confidentiality, integrity, and availability. It matters most on Linux systems that provide graphical sessions, Xwayland compatibility, or TigerVNC remote desktops.

Executive priority

Treat as high priority for Linux graphical and remote desktop environments. It is not evidenced as actively exploited in the provided sources, but the potential impact is broad on systems where local users or remote desktop users can access Xorg, Xwayland, or TigerVNC sessions.

Technical view

The flaw is an uninitialized pointer use in compRedirectWindow(). If compCheckRedirect() cannot allocate a backing pixmap, BadAlloc is returned after window-tree state was partly marked, leaving partially initialized data that may be used later. CVSS 3.1 is 7.8: local, low complexity, low privilege, no user interaction, high CIA impact.

Likely exposure

Exposure is most likely on affected Red Hat Enterprise Linux 6 ELS, 7 ELS, 8, 9, 10 and extended update streams with xorg-x11-server, xorg-x11-server-Xwayland, or tigervnc packages. Debian LTS also published an announcement. Headless systems without these components are likely less exposed.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates local exploitation requiring low privileges, not a remote unauthenticated attack. Public sources here do not provide exploit maturity details.

Researcher notes

Evidence is strongest for the flaw class, CVSS vector, and affected Red Hat package streams. The provided sources do not include exploit code, active exploitation confirmation, or low-level patch mechanics. Validate distribution-specific fixed builds through the cited errata rather than assuming upstream version boundaries.

Mitigation direction

  • Apply relevant vendor security updates from Red Hat or Debian LTS channels.
  • Prioritize graphical workstations, shared Linux servers, VDI, jump hosts, and TigerVNC systems.
  • Check vendor advisories for fixed package versions before making remediation claims.
  • Reduce access to local graphical or VNC sessions where patching is delayed.
  • Track unsupported or extended lifecycle systems separately for update availability.

Validation and detection

  • Inventory hosts with xorg-x11-server, xorg-x11-server-Xwayland, and tigervnc installed.
  • Compare installed package builds against the affected versions in vendor advisories.
  • Confirm update channels include the relevant RHEL ELS, EUS, AUS, TUS, or E4S stream.
  • Review Debian LTS coverage if Debian-based systems use affected X.Org components.
  • Verify patched systems have restarted affected graphical or VNC services.
Prepared
Confidence
high
Sources
11

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-824: 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-2025-26599 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.

1CVSS vectors
5Timeline events
2ADP providers
19Source links

SSVC decision data

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

CVSS vector scores

1 official score

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

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-26599Attack 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. Source timelineredhat

    Reported to Red Hat.

  3. Source timelineredhat

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

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

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Unknown vendorxserverxserver, 0, 22.0.0unaffected
Red HatRed Hat Enterprise Linux 10xorg-x11-server-Xwayland, 0:24.1.5-3.el10_0affected
Red HatRed Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONtigervnc, 0:1.1.0-25.el6_10affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supporttigervnc, 0:1.8.0-36.el7_9affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supportxorg-x11-server, 0:1.20.4-30.el7_9affected
Red HatRed Hat Enterprise Linux 8tigervnc, 0:1.13.1-15.el8_10affected
Red HatRed Hat Enterprise Linux 8.2 Advanced Update Supporttigervnc, 0:1.9.0-15.el8_2.13affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supporttigervnc, 0:1.11.0-8.el8_4.12affected
Red HatRed Hat Enterprise Linux 8.4 Telecommunications Update Servicetigervnc, 0:1.11.0-8.el8_4.12affected
Red HatRed Hat Enterprise Linux 8.4 Update Services for SAP Solutionstigervnc, 0:1.11.0-8.el8_4.12affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supporttigervnc, 0:1.12.0-6.el8_6.13affected
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update Servicetigervnc, 0:1.12.0-6.el8_6.13affected
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP Solutionstigervnc, 0:1.12.0-6.el8_6.13affected
Red HatRed Hat Enterprise Linux 8.8 Extended Update Supporttigervnc, 0:1.12.0-15.el8_8.12affected
Red HatRed Hat Enterprise Linux 9tigervnc, 0:1.14.1-1.el9_5.1affected
Red HatRed Hat Enterprise Linux 9xorg-x11-server, 0:1.20.11-28.el9_6affected
Red HatRed Hat Enterprise Linux 9xorg-x11-server-Xwayland, 0:23.2.7-3.el9_6affected
Red HatRed Hat Enterprise Linux 9.0 Update Services for SAP Solutionstigervnc, 0:1.11.0-22.el9_0.13affected
Red HatRed Hat Enterprise Linux 9.2 Extended Update Supporttigervnc, 0:1.12.0-14.el9_2.10affected
Red HatRed Hat Enterprise Linux 9.4 Extended Update Supporttigervnc, 0:1.13.1-8.el9_4.5affected
Red HatRed Hat Enterprise Linux 6xorg-x11-serverunknown
Red HatRed Hat Enterprise Linux 8xorg-x11-serverunaffected
Red HatRed Hat Enterprise Linux 8xorg-x11-server-Xwaylandunaffected
Weakness

CWE details

CWE-824

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

CWE-824 · source CWE mapping

Access of Uninitialized Pointer

Access of Uninitialized Pointer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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