CVE-2026-56001
Description
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, typically through an X server or an application configured to load untrusted font files.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.3 | 8.8 | 8.5 |
| Attack Vector | Local | Network | Network |
| Attack Complexity | Low | Low | High |
| Privileges Required | Low | Low | Low |
| User Interaction | Required | None | None |
| Scope | Unchanged | Unchanged | Changed |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
