High severity · published Jul 8, 2026
CVE-2026-56003
libXfont2 computeProps Property Buffer Heap Buffer Overflow
8.8
CVSS
0.4%
EPSS
No
On KEV
Description
A heap buffer overflow due to missing size checking in the property buffer when parsing PCF files in libXfont2 ComputeScaledProperties() before libXfont2 before 2.0.8 could be used by attackers using authenticated X clients to execute code within the X server.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
libXfont2 · X.Org
before 2.0.8 · source: vendor
LI
Libxfont · X
2.0.0 before 2.0.8 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56003
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-56003
Patch
https://gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/dff957a5158da038a282a59a31fe736702732939
Mailing List
https://www.openwall.com/lists/oss-security/2026/07/08/1
More from libXfont2
8.8
CVE-2026-56002
libXfont2 PCF Font Parsing Heap Buffer Overflow
8.8
CVE-2026-56001
libXfont2 BitmapScaleBitmaps Integer Overflow Heap Buffer Overflow