CVE-2026-58172 Ocelot - IP Allow/Block List Bypass for WebSocket Upgrade Requests
Attackers can bypass IP allow/block lists in Ocelot API Gateway by sending WebSocket upgrade requests, accessing protected downstream services.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-58172?
CVE-2026-58172 is a critical vulnerability in ThreeMammals Ocelot, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-288
Which versions are affected by CVE-2026-58172?
How do I fix CVE-2026-58172?
No fix has been published for CVE-2026-58172 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-58172 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58172 exists.
Sources
Also known as GHSA-wc9q-87f2-4983.