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CVE-2026-56002— libXfont2 PCF Font Parsing Heap Buffer Overflow

CVSS 8.5 · High EPSS 0.41% · P34

Possible ATT&CK Techniques 1AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 1

VendorProductVersion RangeStatus
X.OrglibXfont2< 2.0.8affected
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I. Basic Information for CVE-2026-56002

Vulnerability Information
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Vulnerability Title
libXfont2 PCF Font Parsing Heap Buffer Overflow
Source: CVE Program / CVE List V5
Vulnerability Description
A heap bufferflow in pcfReadFont() due to missing glyph bounds checking in libXfont2 before 2.0.8  allows attackers authenticated as X client to execute code within the X server.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
堆缓冲区溢出
Source: CVE Program / CVE List V5
Vulnerability Title
libXfont 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
libXfont libXfont是libXfont团队的一款处理X Window系统字体的库。 libXfont 2.0.8之前版本存在缓冲区错误漏洞，该漏洞源于pcfReadFont()函数中缺少字形边界检查，导致堆缓冲区溢出，可能允许通过身份验证的X客户端攻击者在X服务器中执行代码。
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

VendorProductAffected VersionsCPESubscribe
X.OrglibXfont2 0 ~ 2.0.8 -

II. Public POCs for CVE-2026-56002

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III. Intelligence Information for CVE-2026-56002

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Patches & Fixes for CVE-2026-56002 (1)

Mailing List Discussions for CVE-2026-56002 (1)

Same Patch Batch · X.Org · 2026-07-08 · 5 CVEs total

CVE-2026-559998.5 HIGHxorg-server / xwayland glamor font atlas Heap Buffer Overflow
CVE-2026-560018.5 HIGHlibXfont2 BitmapScaleBitmaps Integer Overflow Heap Buffer Overflow
CVE-2026-560038.5 HIGHlibXfont2 computeProps Property Buffer Heap Buffer Overflow
CVE-2026-56000xorg-x11-server / xwayland GLX contextTags Use-After-Free in CommonMakeCurrent()

IV. Related Vulnerabilities

Same product: libXfont2
Same vendor: X.Org
Same weakness: CWE-122

V. Comments for CVE-2026-56002

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