Vulnerability in Threemammals Ocelot
CVE-2026-58172
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.006 (44.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Threemammals Ocelot — versions 0, f156fd4017ca25025fffdad8ec56c1d657dfb402
Weakness classification (CWE)
References
- github.com/ThreeMammals/Ocelot/issues/2403 (technical-description, exploit)
- github.com/ThreeMammals/Ocelot/pull/2406 (issue-tracking)
- github.com/ThreeMammals/Ocelot/commit/f156fd4017ca25025fffdad8ec56c1d657dfb402 (patch)
- www.vulncheck.com/advisories/ocelot-ip-allow-block-list-bypass-for-websocket-up… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-58172?
- CVE-2026-58172 is a critical-severity vulnerability in Threemammals Ocelot, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 9.1/10. Published 2026-06-30.
- How severe is CVE-2026-58172?
- Critical severity. CVSS v3 base score is 9.1 out of 10.