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Full vulnerability report · 2023
CVE-2023-3138High confidence

A vulnerability was found in libX11

n/a · libX11

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-43823

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

A vulnerability was found in libX11. The security flaw occurs because the functions in src/InitExt.c in libX11 do not check that the values provided for the Request, Event, or Error IDs are within the bounds of the arrays that those functions write to, using those IDs as array indexes. They trust that they were called with values provided by an Xserver adhering to the bounds specified in the X11 protocol, as all X servers provided by X.Org do. As the protocol only specifies a single byte for these values, an out-of-bounds value provided by a malicious server (or a malicious proxy-in-the-middle) can only overwrite other portions of the Display structure and not write outside the bounds of the Display structure itself, possibly causing the client to crash with this memory corruption.

What

A vulnerability was found in libX11. The security flaw occurs because the functions in src/InitExt.c in libX11 do not check that the values provided for the Request, Event, or Error IDs are within the bounds of the arrays that those functions write to, using those IDs as array indexes. They trust that they were called with values provided by an Xserver adhering to the bounds specified in the X11 protocol, as all X servers provided by X.Org do. As the protocol only specifies a single byte for these values, an out-of-bounds value provided by a malicious server (or a malicious proxy-in-the-middle) can only overwrite other portions of the Display structure and not write outside the bounds of the Display structure itself, possibly causing the client to crash with this memory corruption.

Why

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

A vulnerability was found in libX11. The security flaw occurs because the functions in src/InitExt.c in libX11 do not check that the values provided for the Request, Event, or Error IDs are within the bounds of the arrays that those functions write to, using those IDs as array indexes. They trust that they were called with values provided by an Xserver adhering to the bounds specified in the X11 protocol, as all X servers provided by X.Org do. As the protocol only specifies a single byte for these values, an out-of-bounds value provided by a malicious server (or a malicious proxy-in-the-middle) can only overwrite other portions of the Display structure and not write outside the bounds of the Display structure itself, possibly causing the client to crash with this memory corruption.

Why

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Restriction of Operations within the Bounds of a Memory Buffer → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-119

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer. The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-119
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2024-1086IBM QRadar SIEM: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, einen Denial-of-Service-Zustand herbeizuführen, vertrauliche Informationen offenzulegen, Dateien zu manipulieren, seine Privilegien zu erweitern, einen Cross-Site-Scripting (XSS)-Angriff durchzuführen oder einen nicht spezifizierten Angriff auszuführen.

Official advisory
BSI · German · WID-SEC-W-2024-0794Dell ECS: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Dell ECS ausnutzen, um seine Privilegien zu erweitern, beliebigen Programmcode mit Administratorrechten auszuführen, Informationen offenzulegen, Dateien zu manipulieren, einen Cross-Site-Scripting-Angriff durchzuführen, Sicherheitsvorkehrungen zu umgehen oder einen Denial of Service Zustand herbeizuführen.

Official advisory
BSI · German · WID-SEC-W-2023-2917Xerox FreeFlow Print Server: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Xerox FreeFlow Print Server ausnutzen, um die Vertraulichkeit, Verfügbarkeit und Integrität des Systems zu gefährden.

Official advisory
BSI · German · WID-SEC-W-2023-1485X.Org X11: Schwachstelle ermöglicht Denial of Service

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in X.Org X11 ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory
CERT-FR · French · CERTFR-2025-AVI-0756Multiples vulnérabilités dans les produits VMware

d?id=CVE-2023-27536 Référence CVE CVE-2023-27537 https://www.cve.org/CVERecord?id=CVE-2023-27537 Référence CVE CVE-2023-27538 https://www.cve.org/CVERecord?id=CVE-2023-27538 Référence CVE CVE-2023-28320 https://www.cve.org/CVERecord?id=CVE-2023-28320 Référence CVE CVE-2023-28321 https://www.cve.org/CVERecord?id=CVE-2023-28321 Référence CVE CVE-2023-28322 https://www.cve.org/CVERecord?id=CVE-2023-28322 Référence CVE CVE-2023-28484 https://www.cve.org/CVERecord?id=CVE-2023-28484 Référence CVE CVE-2023-29383 https://www.cve.org/CVERecord?id=CVE-2023-29383 Référence CVE CVE-2023-29469 https://www.cve.org/CVERecord?id=CVE-2023-29469 Référence CVE CVE-2023-3138 https://www.cve.org/CVERecord?id=CVE-2023-3138 Référence CVE CVE-2023-31437 https://www.cve.org/CVERecord?id=CVE-2023-31437 Référence CVE CVE-2023-31438 https://www.cve.org/CVERecord?id=CVE-2023-31438 Référence CVE CVE-2023-31439 https://www.cve.org/CVERecord?id=CVE-2023-31439 Référence CVE CVE-2023-31484 https://www.cve.org/CVERecord?id=CVE-2023-31484 Référence CVE CVE-2023-31486 https://www.cve.org/CVERecord?id=CVE-2023-31486 Référence CVE CVE-2023-34055 https://www.cve.org/CVERecord?id=CVE-2023-34055 Référence CVE CVE-2023-34969 https://www.cve.org/CVERecord?id=CVE-2023-34969 Référence CVE CVE-2023-35116 https://www.cve.org/CVERecord?id=C

Official advisory
CERT-FR · French · CERTFR-2024-AVI-0506Multiples vulnérabilités dans Juniper Secure Analytics

d?id=CVE-2023-28322 Référence CVE CVE-2023-28328 https://www.cve.org/CVERecord?id=CVE-2023-28328 Référence CVE CVE-2023-28464 https://www.cve.org/CVERecord?id=CVE-2023-28464 Référence CVE CVE-2023-28486 https://www.cve.org/CVERecord?id=CVE-2023-28486 Référence CVE CVE-2023-28487 https://www.cve.org/CVERecord?id=CVE-2023-28487 Référence CVE CVE-2023-28772 https://www.cve.org/CVERecord?id=CVE-2023-28772 Référence CVE CVE-2023-30456 https://www.cve.org/CVERecord?id=CVE-2023-30456 Référence CVE CVE-2023-31083 https://www.cve.org/CVERecord?id=CVE-2023-31083 Référence CVE CVE-2023-31084 https://www.cve.org/CVERecord?id=CVE-2023-31084 Référence CVE CVE-2023-3138 https://www.cve.org/CVERecord?id=CVE-2023-3138 Référence CVE CVE-2023-3141 https://www.cve.org/CVERecord?id=CVE-2023-3141 Référence CVE CVE-2023-31436 https://www.cve.org/CVERecord?id=CVE-2023-31436 Référence CVE CVE-2023-3161 https://www.cve.org/CVERecord?id=CVE-2023-3161 Référence CVE CVE-2023-3212 https://www.cve.org/CVERecord?id=CVE-2023-3212 Référence CVE CVE-2023-32324 https://www.cve.org/CVERecord?id=CVE-2023-32324 Référence CVE CVE-2023-32360 https://www.cve.org/CVERecord?id=CVE-2023-32360 Référence CVE CVE-2023-3268 https://www.cve.org/CVERecord?id=CVE-2023-3268 Référence CVE CVE-2023-33203 https://www.cve.org/CVERecord?id=CVE-2023-

Official advisory
CERT-FR · French · CERTFR-2024-AVI-0385Multiples vulnérabilités dans les produits IBM

rd?id=CVE-2023-2597 Référence CVE CVE-2023-26545 https://www.cve.org/CVERecord?id=CVE-2023-26545 Référence CVE CVE-2023-27043 https://www.cve.org/CVERecord?id=CVE-2023-27043 Référence CVE CVE-2023-28322 https://www.cve.org/CVERecord?id=CVE-2023-28322 Référence CVE CVE-2023-28328 https://www.cve.org/CVERecord?id=CVE-2023-28328 Référence CVE CVE-2023-28772 https://www.cve.org/CVERecord?id=CVE-2023-28772 Référence CVE CVE-2023-29483 https://www.cve.org/CVERecord?id=CVE-2023-29483 Référence CVE CVE-2023-30456 https://www.cve.org/CVERecord?id=CVE-2023-30456 Référence CVE CVE-2023-31084 https://www.cve.org/CVERecord?id=CVE-2023-31084 Référence CVE CVE-2023-3138 https://www.cve.org/CVERecord?id=CVE-2023-3138 Référence CVE CVE-2023-3141 https://www.cve.org/CVERecord?id=CVE-2023-3141 Référence CVE CVE-2023-31436 https://www.cve.org/CVERecord?id=CVE-2023-31436 Référence CVE CVE-2023-3161 https://www.cve.org/CVERecord?id=CVE-2023-3161 Référence CVE CVE-2023-3212 https://www.cve.org/CVERecord?id=CVE-2023-3212 Référence CVE CVE-2023-32324 https://www.cve.org/CVERecord?id=CVE-2023-32324 Référence CVE CVE-2023-32360 https://www.cve.org/CVERecord?id=CVE-2023-32360 Référence CVE CVE-2023-3268 https://www.cve.org/CVERecord?id=CVE-2023-3268 Référence CVE CVE-2023-33203 https://www.cve.org/CVERecord?id=CVE-2023-

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
libX11 1.8.6
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 28 Jun 2023 · Last source change 2 Aug 2024, 06:48 UTC · CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2023-43823
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-3138 · cve.blacktree.nl