---
id: CVE-2026-93578
title: A flaw was found in Netty's Online Certificate Status Protocol (OCSP) Client
summary: >-
  A flaw was found in Netty's Online Certificate Status Protocol (OCSP) Client.
  The client fails to verify the 'id-kp-OCSPSigning' Extended Key Usage (EKU) in
  OCSP responder certificates. A remote attacker, holding any valid certificate
  is…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-1035
vendor: Red Hat
product: netty-handler-ssl-ocsp
affected:
  - netty-handler-ssl-ocsp (all versions)
published: '2026-09-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T19:06:08.407'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93578'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-93578'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536969'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-93578'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93578.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-93578'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93578'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-18T14:41:00.538935Z'
ingestedAt: '2026-09-18T11:40:03.682Z'
epss: 0.00293
epssPercentile: 0.19393
---

## Overview

A flaw was found in Netty's Online Certificate Status Protocol (OCSP) Client. The client fails to verify the 'id-kp-OCSPSigning' Extended Key Usage (EKU) in OCSP responder certificates. A remote attacker, holding any valid certificate issued by the same Certificate Authority (CA), can exploit this by forging 'GOOD' OCSP responses for revoked certificates. This bypasses certificate revocation checks, allowing applications using Netty's OCSP Client to accept certificates that should have been revoked, leading to an authorization bypass.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat build of Apache Camel for Spring Boot 4 · no fix planned: Red Hat build of Apache Camel for Spring Boot 4 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93578.json)