CVE-2026-58172

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.

CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0041

Probability of exploitation

0.33%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-288 CWE-288

References

Other 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

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-58172? +

CVE-2026-58172 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0041, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-58172? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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