---
id: CVE-2026-90668
title: >-
  The webserver in UnrealIRCd 6.0.5 through 6.2.6 before 6.2.7 does not limit
  the number of HTTP request headers, which allows remote attackers to cause a
  denial of service (memory consumption and unresponsive server) via an HTTP
  request w…
summary: >-
  The webserver in UnrealIRCd 6.0.5 through 6.2.6 before 6.2.7 does not limit
  the number of HTTP request headers, which allows remote attackers to cause a
  denial of service (memory consumption and unresponsive server) via an HTTP
  request w…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
vendor: UnrealIRCd
product: UnrealIRCd
affected:
  - UnrealIRCd >= 6.0.5 < 6.2.7
published: '2026-09-13'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T20:00:03.713'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90668'
references:
  - url: 'https://forums.unrealircd.org/viewtopic.php?t=9483'
    label: cve@mitre.org
  - url: 'https://www.unrealircd.org/'
    label: cve@mitre.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90668.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-90668'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-90668'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00332
epssPercentile: 0.26627
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-14T18:13:05.650571Z'
ingestedAt: '2026-09-14T15:23:07.477Z'
---

## Overview

The webserver in UnrealIRCd 6.0.5 through 6.2.6 before 6.2.7 does not limit the number of HTTP request headers, which allows remote attackers to cause a denial of service (memory consumption and unresponsive server) via an HTTP request with an unlimited number of headers, if a websocket or JSON-RPC listener is enabled (disabled by default).

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90668.json)