CVE-2026-58172

Ocelot - IP Allow/Block List Bypass for WebSocket Upgrade Requests

CVSS 9.3 CRITICALCWE-288

Vexday Risk Score

45Attention

SSVC decision (CISA)

Attend

PoC available → attend closely

CVSS 9.3EPSS —KEV nãoPoC públicaNuclei —Metasploit —Patch referenciado

Lifecycle

30 Jun 2026Published on NVD

Recommendation: Plan a near-term fix — a public PoC already exists.

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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Affected products

ThreeMammals · Ocelot

public PoCs found — 1

cve_referencegithub.com/ThreeMammals/Ocelot/issues/2403unverified

⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.

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References

https://github.com/ThreeMammals/Ocelot/commit/f156fd4017ca25025fffdad8ec56c1d657dfb402 https://github.com/ThreeMammals/Ocelot/issues/2403 https://github.com/ThreeMammals/Ocelot/pull/2406 https://www.vulncheck.com/advisories/ocelot-ip-allow-block-list-bypass-for-websocket-upgrade-requests