What’s Vulnerable › Vulnerabilities

CVE-2026-58172: Ocelot - IP Allow/Block List Bypass for WebSocket Upgrade Requests

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-30 · updated 2026-10-25
• Weakness: CWE-288

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.

Affected products

• ThreeMammals Ocelot: through 24.1.0

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

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