CVE-2026-56001
published 2026-07-08CVE-2026-56001: A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server…
PriorityP358high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
EPSS
0.62%
47.5th percentile
A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| ubuntu | libxfont | — | — |
| x.org | libxfont2 | < 2.0.8 | 2.0.8 |
| x.org | libxfont2 | — | — |
| x | libxfont | >= 2.0.0 < 2.0.8 | 2.0.8 |
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vendor_ubuntu8.8HIGH
vendor_redhat8.5HIGH
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Ubuntu
libXfont vulnerabilities
vendor_ubuntu·2026-07-20·CVSS 8.8
CVE-2026-56003 [HIGH] libXfont vulnerabilities
Title: libXfont vulnerabilities
Summary: Several security issues were fixed in libXfont.
It was discovered that libXfont incorrectly handled scaling bitmap
fonts, leading to a heap buffer overflow. An attacker able to access
the X server could use this issue to cause libXfont to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2026-56001)
It was discovered that libXfont did not properly check glyph bounds
when reading PCF fonts, leading to a heap buffer overflow. An
authenticated X client could use this issue to cause libXfont to
crash, resulting in a denial of service, or possibly execute arbitrary
code. (CVE-2026-56002)
It was discovered that libXfont did not properly check the size of the
property buffer when parsing PCF fonts, leading to a heap buff
Red Hat
libXfont2: BitmapScaleBitmaps Integer Overflow Heap Buffer Overflow
vendor_redhat·2026-07-08·CVSS 8.5
CVE-2026-56001 [HIGH] libXfont2: BitmapScaleBitmaps Integer Overflow Heap Buffer Overflow
libXfont2: BitmapScaleBitmaps Integer Overflow Heap Buffer Overflow
A flaw was found in libXfont2. In the BitmapScaleBitmaps() function, an integer overflow can occur when calculating the memory needed for font glyphs. This overflow leads to a heap buffer overflow, where a smaller-than-required memory buffer is allocated. A local attacker can exploit this by loading a specially crafted PCF font, potentially leading to arbitrary code execution or a denial of service.
Statement: This flaw in libXfont2 is rated as Important. A local attacker could exploit an integer overflow in the `BitmapScaleBitmaps()` function, leading to a heap buffer overflow and potential arbitrary code execution or denial of service. This vulnerability requires the processing of a specially crafted PCF font, typicall
GHSA
A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont
ghsa_unreviewed·2026-07-08
CVE-2026-56001 [HIGH] CWE-122 A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont
A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont
No detection rules found.
No public exploits indexed.
2026-07-08
Published