CVE-2026-50256— Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libxfont2 name length mismatch
Quick assessment
Affected
Red Hat Red Hat Enterprise Linux 10
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
X.Org X Server是X.Org基金会的一款X Window系统显示服务器。Xwayland是Xwayland开源的一个通信协议，规定了显示服务器与其客户机之间的通信方式。 X.Org X server和Xwayland存在安全漏洞，该漏洞源于X服务器与libXfont2库之间最大字体名称长度不匹配导致栈缓冲区溢出，可能导致服务器崩溃或权限提升。
Possible ATT&CK Techniques 2 AI
T1059 · Command and Scripting Interpreter T1203 · Exploitation for Client ExecutionAffected Version Matrix 37
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | 0:24.1.9-4.el10_2.2< * |
unaffected |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | 0:24.1.5-6.el10_0.1< * |
unaffected |
| Red Hat | Red Hat Enterprise Linux 6 | any |
unknown |
| Red Hat | Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION | 0:1.1.0-25.el6_10.18< * |
unaffected |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | 0:1.20.4-35.el7_9< * |
unaffected |
0:1.8.0-36.el7_9.5< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 8 | 0:21.1.3-20.el8_10.2< * |
unaffected |
0:1.20.11-28.el8_10.2< * |
unaffected | ||
0:1.15.0-10.el8_10< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | 0:1.20.10-5.el8_4< * |
unaffected |
0:1.11.0-8.el8_4.16< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | 0:1.20.10-5.el8_4< * |
unaffected |
0:1.11.0-8.el8_4.16< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 0:1.20.11-8.el8_6< * |
unaffected |
0:21.1.3-2.el8_6.7< * |
unaffected | ||
0:1.12.0-6.el8_6.18< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 0:1.20.11-8.el8_6< * |
unaffected |
0:21.1.3-2.el8_6.7< * |
unaffected | ||
0:1.12.0-6.el8_6.18< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 0:1.20.11-19.el8_8< * |
unaffected |
0:21.1.3-13.el8_8.1< * |
unaffected | ||
0:1.12.0-15.el8_8.18< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 0:1.20.11-19.el8_8< * |
unaffected |
0:21.1.3-13.el8_8.1< * |
unaffected | ||
0:1.12.0-15.el8_8.18< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 9 | 0:24.1.9-4.el9_8.2< * |
unaffected |
0:1.20.11-34.el9_8.2< * |
unaffected | ||
0:1.15.0-7.el9_8.2< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:1.20.11-21.el9_2< * |
unaffected |
0:21.1.3-10.el9_2.1< * |
unaffected | ||
0:1.12.0-14.el9_2.15< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | 0:1.20.11-29.el9_4< * |
unaffected |
0:22.1.9-8.el9_4.1< * |
unaffected | ||
0:1.13.1-8.el9_4.10< * |
unaffected | ||
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | 0:1.20.11-34.el9_6< * |
unaffected |
0:23.2.7-6.el9_6.1< * |
unaffected | ||
0:1.14.1-11.el9_6< * |
unaffected |
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I. Basic Information for CVE-2026-50256
Vulnerability Information
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Vulnerability Title
Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libxfont2 name length mismatch
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
栈缓冲区溢出
Source: CVE Program / CVE List V5
Vulnerability Title
X.Org X server和Xwayland 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
X.Org X Server是X.Org基金会的一款X Window系统显示服务器。Xwayland是Xwayland开源的一个通信协议，规定了显示服务器与其客户机之间的通信方式。 X.Org X server和Xwayland存在安全漏洞，该漏洞源于X服务器与libXfont2库之间最大字体名称长度不匹配导致栈缓冲区溢出，可能导致服务器崩溃或权限提升。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | 0:24.1.9-4.el10_2.2 ~ * |
cpe:/o:redhat:enterprise_linux:10.2
|
|
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | 0:24.1.5-6.el10_0.1 ~ * |
cpe:/o:redhat:enterprise_linux_eus:10.0
|
|
| Red Hat | Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION | 0:1.1.0-25.el6_10.18 ~ * |
cpe:/o:redhat:rhel_els:6
|
|
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | 0:1.20.4-35.el7_9 ~ * |
cpe:/o:redhat:rhel_els:7
|
|
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | 0:1.8.0-36.el7_9.5 ~ * |
cpe:/o:redhat:rhel_els:7
|
|
| Red Hat | Red Hat Enterprise Linux 8 | 0:21.1.3-20.el8_10.2 ~ * |
cpe:/a:redhat:enterprise_linux:8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8 | 0:1.20.11-28.el8_10.2 ~ * |
cpe:/a:redhat:enterprise_linux:8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8 | 0:1.15.0-10.el8_10 ~ * |
cpe:/a:redhat:enterprise_linux:8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | 0:1.20.10-5.el8_4 ~ * |
cpe:/a:redhat:rhel_aus:8.4::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | 0:1.11.0-8.el8_4.16 ~ * |
cpe:/a:redhat:rhel_aus:8.4::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | 0:1.20.10-5.el8_4 ~ * |
cpe:/a:redhat:rhel_aus:8.4::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | 0:1.11.0-8.el8_4.16 ~ * |
cpe:/a:redhat:rhel_aus:8.4::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 0:1.20.11-8.el8_6 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 0:21.1.3-2.el8_6.7 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 0:1.12.0-6.el8_6.18 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 0:1.20.11-8.el8_6 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 0:21.1.3-2.el8_6.7 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 0:1.12.0-6.el8_6.18 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 0:1.20.11-19.el8_8 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 0:21.1.3-13.el8_8.1 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 0:1.12.0-15.el8_8.18 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 0:1.20.11-19.el8_8 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 0:21.1.3-13.el8_8.1 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 0:1.12.0-15.el8_8.18 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9 | 0:24.1.9-4.el9_8.2 ~ * |
cpe:/a:redhat:enterprise_linux:9::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9 | 0:1.20.11-34.el9_8.2 ~ * |
cpe:/a:redhat:enterprise_linux:9::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9 | 0:1.15.0-7.el9_8.2 ~ * |
cpe:/a:redhat:enterprise_linux:9::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:1.20.11-21.el9_2 ~ * |
cpe:/a:redhat:rhel_e4s:9.2::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:21.1.3-10.el9_2.1 ~ * |
cpe:/a:redhat:rhel_e4s:9.2::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:1.12.0-14.el9_2.15 ~ * |
cpe:/a:redhat:rhel_e4s:9.2::appstream
|
|
II. Public POCs for CVE-2026-50256
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
Premium
No public POC found.
Login to generate AI POCIII. Intelligence Information for CVE-2026-50256
请登录查看更多情报信息。
Patches & Fixes for CVE-2026-50256 (1)
Vendor Advisories for CVE-2026-50256 (26)
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🔗 RHSA-2026:46456 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36633 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:46460 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:46385 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:28923 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:26562 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:26566 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:46392 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36087 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:46382 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36634 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36086 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36791 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36632 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:38502 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36083 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36798 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36085 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36792 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:46473 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:36768 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
-
🔗 RHSA-2026:46377 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
-
🔗 RHSA-2026:38810 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
Mailing List Discussions for CVE-2026-50256 (1)
Other References for CVE-2026-50256 (4)
Same Patch Batch · Red Hat · 2026-06-05 · 11 CVEs total
| CVE-2026-11332 | 7.8 HIGH | Ansible-core: argument injection in ansible-galaxy role install leads to arbitrary code ex |
| CVE-2026-50257 | 7.8 HIGH | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in misyncdestro |
| CVE-2026-50259 | 7.8 HIGH | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in xkb s |
| CVE-2026-50258 | 7.8 HIGH | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in xkb k |
| CVE-2026-50260 | 7.8 HIGH | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in freecounter( |
| CVE-2026-50261 | 7.8 HIGH | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangeco |
| CVE-2026-50264 | 7.8 HIGH | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: out-of-bounds heap write in dr |
| CVE-2026-50262 | 5.5 MEDIUM | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: out-of-bounds read/write in gl |
| CVE-2026-50263 | 5.5 MEDIUM | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free information dis |
| CVE-2026-9088 | 2.7 LOW | Keycloak: keycloak: information disclosure due to user profile permission bypass |
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V. Comments for CVE-2026-50256
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