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CVE Record

CVE-2025-49178: Xorg-x11-server-xwayland: xorg-x11-server: tigervnc: unprocessed client request due to bytes to ignore

A flaw was found in the X server's request handling. Non-zero 'bytes to ignore' in a client's request can cause the server to skip processing another client's request, potentially leading to a denial of service.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a denial-of-service issue in X server request handling. A low-privileged local client can disrupt processing of another client’s request, potentially making graphical sessions or VNC-backed workflows unavailable. It does not indicate data theft or code execution in the supplied sources.

Executive priority

Treat as a moderate availability risk. It is not a known active exploitation emergency from the supplied evidence, but shared Linux graphical environments should be patched in normal security maintenance windows, sooner where outages would affect operations.

Technical view

The flaw involves non-zero “bytes to ignore” handling in client requests. Affected Xorg/Xwayland/TigerVNC server components may skip another client request, causing availability impact. CVSS 3.1 is 5.5 with AV:L/PR:L/UI:N and availability high.

Likely exposure

Exposure is most likely on Red Hat systems running affected xorg-x11-server, xorg-x11-server-Xwayland, or TigerVNC packages, especially multi-user desktops, graphical servers, VDI, or VNC environments where low-privileged users can access sessions.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. The CVSS vector indicates local access with low privileges is required, no user interaction is needed, and the impact is limited to availability.

Researcher notes

Evidence is strongest for Red Hat package streams and the CVE description. The bundle does not provide proof-of-concept details, exploit telemetry, or upstream fixed-version specifics beyond RHSA references. Avoid assuming remote exploitation despite TigerVNC package impact.

Mitigation direction

  • Identify affected Red Hat package versions across RHEL and lifecycle add-on environments.
  • Apply the applicable Red Hat RHSA updates for each affected package stream.
  • Prioritize shared graphical, VDI, and TigerVNC systems with untrusted or many users.
  • Check vendor guidance for any stream-specific remediation or support constraints.

Validation and detection

  • Inventory installed xorg-x11-server, Xwayland, and TigerVNC package versions.
  • Map hosts to affected RHEL versions and lifecycle channels listed in the CVE bundle.
  • Confirm relevant Red Hat errata are installed or scheduled for deployment.
  • Review service exposure for shared graphical sessions and VNC usage.
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

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cwe · low confidence lookup

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CVE-2025-49178 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
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
34Source links

SSVC decision data

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

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
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6redhat

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2025-49178Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
X.Orgxwaylandxwayland, 0unaffected
Red HatRed Hat Enterprise Linux 10xorg-x11-server-Xwayland, 0:24.1.5-4.el10_0affected
Red HatRed Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONtigervnc, 0:1.1.0-25.el6_10.1affected
Red HatRed Hat Enterprise Linux 7.7 Advanced Update Supporttigervnc, 0:1.8.0-17.el7_7.1affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supportxorg-x11-server, 0:1.20.4-32.el7_9affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supporttigervnc, 0:1.8.0-36.el7_9.2affected
Red HatRed Hat Enterprise Linux 8xorg-x11-server, 0:1.20.11-26.el8_10affected
Red HatRed Hat Enterprise Linux 8xorg-x11-server-Xwayland, 0:21.1.3-18.el8_10affected
Red HatRed Hat Enterprise Linux 8tigervnc, 0:1.15.0-7.el8_10affected
Red HatRed Hat Enterprise Linux 8.2 Advanced Update Supporttigervnc, 0:1.9.0-15.el8_2.14affected
Red HatRed Hat Enterprise Linux 8.2 Advanced Update Supportxorg-x11-server, 0:1.20.6-4.el8_2affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportxorg-x11-server, 0:1.20.10-2.el8_4affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supporttigervnc, 0:1.11.0-8.el8_4.13affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Onxorg-x11-server, 0:1.20.10-2.el8_4affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Ontigervnc, 0:1.11.0-8.el8_4.13affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supporttigervnc, 0:1.12.0-6.el8_6.14affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportxorg-x11-server-Xwayland, 0:21.1.3-2.el8_6.4affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportxorg-x11-server, 0:1.20.11-5.el8_6.3affected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-Ontigervnc, 0:1.12.0-6.el8_6.14affected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-Onxorg-x11-server-Xwayland, 0:21.1.3-2.el8_6.4affected
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update Servicetigervnc, 0:1.12.0-6.el8_6.14affected
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update Servicexorg-x11-server-Xwayland, 0:21.1.3-2.el8_6.4affected
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update Servicexorg-x11-server, 0:1.20.11-5.el8_6.3affected
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP Solutionstigervnc, 0:1.12.0-6.el8_6.14affected
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP Solutionsxorg-x11-server-Xwayland, 0:21.1.3-2.el8_6.4affected
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP Solutionsxorg-x11-server, 0:1.20.11-5.el8_6.3affected
Red HatRed Hat Enterprise Linux 8.8 Extended Update Support Long-Life Add-Onxorg-x11-server, 0:1.20.11-16.el8_8affected
Red HatRed Hat Enterprise Linux 8.8 Extended Update Support Long-Life Add-Onxorg-x11-server-Xwayland, 0:21.1.3-11.el8_8affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicexorg-x11-server, 0:1.20.11-16.el8_8affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicetigervnc, 0:1.12.0-15.el8_8.14affected
Weakness

CWE details

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Improper Locking

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