---
title: "CVE-2026-91189: GUIX - Buffer Overflow"
description: "GUIX binary resource loader contains a buffer overflow caused by improper validation of font page glyph ranges, letting attackers write out-of-bounds data, exploit requires crafted font files."
url: https://panop.io/threat-heartbeat/CVE-2026-91189/
---

# CVE-2026-91189 GUIX - Buffer Overflow

GUIX binary resource loader contains a buffer overflow caused by improper validation of font page glyph ranges, letting attackers write out-of-bounds data, exploit requires crafted font files.

CVSS base score 7.1 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-91189)

## Details

Type

Buffer Overflow

Impact

Remote Code Execution, Denial Of Service

CVSS vector

CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Published

20 October 2026

Updated

21 October 2026

Weakness

[CWE-190](https://cwe.mitre.org/data/definitions/190.html)

## Vendor fix

Update to the latest version with proper glyph range validation and buffer size checks.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-91189](https://nvd.nist.gov/vuln/detail/CVE-2026-91189)
- [https://github.com/eclipse-threadx/guix/security/advisories/GHSA-hgcj-22cg-4hfv](https://github.com/eclipse-threadx/guix/security/advisories/GHSA-hgcj-22cg-4hfv)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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