> CVE-2026-50256 [HIGH]

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PUBLISHED
2026-06-05 12:16
MODIFIED
2026-06-05 12:16
CVSS_SCORE V3
7.8
EPSS (Prob. Exploit)
0.21%
Top 89.2%
DATA SOURCES:
NVD 🔗 2026-06-05 RED HAT 🔗 2026-06-07 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 MSRC 🔗 2026-11-02

> DESCRIPTION

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EXPLOITABILITY
1.8
IMPACT
5.9

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Local (L)
Exploit nécessite un accès local au système
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
Low (L)
Authentifié avec compte utilisateur basique
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-121

> CWE DETAILED DESCRIPTIONS

CWE-121: Stack-based Buffer Overflow - The product writes past the end of a buffer that was allocated on the stack.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: xorg-x11-server-Xwayland security, bug fix, and enhancement update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability...
Red Hat Security Advisory: xorg-x11-server-Xwayland security, bug fix, and enhancement update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability...
Red Hat Security Advisory: xorg-x11-server security, bug fix, and enhancement update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring...
Red Hat Security Advisory: xorg-x11-server security, bug fix, and enhancement update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring...
Red Hat Security Advisory: xorg-x11-server-Xwayland security, bug fix, and enhancement update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerabilit...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System...
Red Hat Security Advisory: xorg-x11-server security update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Import...
Red Hat Security Advisory: xorg-x11-server security update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Com...
Red Hat Security Advisory: xorg-x11-server security update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Import...
Red Hat Security Advisory: xorg-x11-server security update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 7 Extended Lifecycle Support. Red Hat Product Security has rated this update as having a security impact of Important. A Co...
Red Hat Security Advisory: xorg-x11-server security update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On. Red...
Red Hat Security Advisory: xorg-x11-server security update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On. Red...
Red Hat Security Advisory: xorg-x11-server-Xwayland security update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Importa...
Red Hat Security Advisory: xorg-x11-server-Xwayland security update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact...
Red Hat Security Advisory: xorg-x11-server-Xwayland security update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact...
Red Hat Security Advisory: xorg-x11-server-Xwayland security update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 10.0 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Import...
Red Hat Security Advisory: xorg-x11-server security update
An update for xorg-x11-server is now available for Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service. Red Hat Product S...
Red Hat Security Advisory: xorg-x11-server-Xwayland security update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service. Red Hat...
Red Hat Security Advisory: xorg-x11-server-Xwayland security update
An update for xorg-x11-server-Xwayland is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On. Red Hat Pr...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On. Red Hat Pr...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 7 Extended Lifecycle Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vu...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vul...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service. Red Hat Product Security...
Red Hat Security Advisory: tigervnc security update
An update for tigervnc is now available for Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION. Red Hat Product Security has rated this update as having a security impact of Important...

> RED HAT SEVERITY ASSESSMENT

THREAT SEVERITY
Important

> HISTORIQUE DES MODIFICATIONS

Première apparition
05/06/2026 12:16
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-121: Stack-based Buffer Overflow - A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a para...
Nouvelle valeur:
CWE-121: Stack-based Buffer Overflow - The product writes past the end of a buffer that was allocated on the stack.
📊 ENRICHISSEMENT 01/07/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-121: Stack-based Buffer Overflow - A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a para...
📊 ENRICHISSEMENT 07/06/2026 05:01
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
N/A
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/06/2026 05:01
REDHAT
Champ modifié: Red Hat
Ancienne valeur:
Non
Nouvelle valeur:
Oui
Total des modifications: 4 Dernière mise à jour: 6 days ago

> REFERENCES

https://access.redhat.com/security/cve/CVE-2026-50256
https://bugzilla.redhat.com/show_bug.cgi?id=2485380
https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fc...
https://lists.x.org/archives/xorg-announce/2026-June/003702.html
https://redhat.atlassian.net/browse/PSIRTSUPT-16950
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