---
id: CVE-2026-88648
title: >-
  Incomplete X.509 implementation in GnuTLS v3.8.13 allows attackers controlling
  a subordinate Certificate Authority to bypass cross-domain PKI restrictions
  and issue unauthorized certificates.
summary: >-
  Incomplete X.509 implementation in GnuTLS v3.8.13 allows attackers controlling
  a subordinate Certificate Authority to bypass cross-domain PKI restrictions
  and issue unauthorized certificates.
severity: high
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:33:42.423'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88648'
references:
  - url: 'https://gist.github.com/lkloliver/1f2a97cb8d0b31aa27b6bd0354358d7d'
    label: cve@mitre.org
  - url: 'https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.10'
    label: cve@mitre.org
  - url: 'https://www.rfc-editor.org/rfc/rfc5280#section-6.1.4'
    label: cve@mitre.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88648.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-88648'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2548200'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-88648'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88648'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
ingestedAt: '2026-10-08T20:06:22.191Z'
epss: 0.00203
epssPercentile: 0.10147
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
  - hardened_images
  - openshift_container_platform 4
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cvssSource: vendor
cwe:
  - CWE-295
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-19T15:06:45.918878Z'
scores:
  vendor: 7.4
  adp: 3.7
---

## Overview

Incomplete X.509 implementation in GnuTLS v3.8.13 allows attackers controlling a subordinate Certificate Authority to bypass cross-domain PKI restrictions and issue unauthorized certificates.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Hardened Images, … · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88648.json)