---
id: CVE-2026-58172
title: Ocelot - IP Allow/Block List Bypass for WebSocket Upgrade Requests
summary: >-
  Ocelot through 24.1.0, fixed in commit f156fd4, contains a security control
  bypass vulnerability that allows denied clients to circumvent IP-based access
  restrictions by sending WebSocket upgrade requests. The WebSocket upgrade
  pipeline …
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-288
vendor: ThreeMammals
product: Ocelot
affected:
  - Ocelot <= 24.1.0
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-07-02T03:56:10.595991Z'
exploitAvailable: true
published: '2026-06-30'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T14:06:52.690Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-58172'
references:
  - url: 'https://github.com/ThreeMammals/Ocelot/issues/2403'
    label: Researcher Disclosure
  - url: 'https://github.com/ThreeMammals/Ocelot/pull/2406'
    label: Fix PR
  - url: >-
      https://github.com/ThreeMammals/Ocelot/commit/f156fd4017ca25025fffdad8ec56c1d657dfb402
    label: Fix Commit
  - url: >-
      https://www.vulncheck.com/advisories/ocelot-ip-allow-block-list-bypass-for-websocket-upgrade-requests
tags:
  - cve.org
  - exploit-available
epss: 0.00565
epssPercentile: 0.47197
ingestedAt: '2026-11-08T14:51:22.305Z'
---

## Overview

Ocelot through 24.1.0, fixed in commit f156fd4, contains a security control bypass vulnerability that allows denied clients to circumvent IP-based access restrictions by sending WebSocket upgrade requests. The WebSocket upgrade pipeline branch configured via MapWhen in OcelotPipelineExtensions.cs omits SecurityMiddleware, causing requests from blocked IP addresses to be proxied to downstream services without enforcement of the configured allow/block list.

## Affected

- `Ocelot <= 24.1.0`

## Remediation

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