CVE-2026-58172
Ocelot - IP Allow/Block List Bypass for WebSocket Upgrade Requests
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Ocelot - IP Allow/Block List Bypass for WebSocket Upgrade Requests
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.
- Record
CVE-2026-58172- CVSS 4.0
- 9.3 Critical
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 - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-288
- Updated
- 2026-11-08
EUVDEUVD-2026-40353
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.
- Record
EUVD-2026-40353- CVSS 4.0
- 9.3 Critical
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 - Updated
- 2026-11-08
GitHub AdvisoriesGHSA-wc9q-87f2-4983
Ocelot through 24.1.0, fixed in commit f156fd4, contains a security control bypass vulnerability...
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.
- Record
GHSA-wc9q-87f2-4983- CVSS 4.0
- 9.3 Critical
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-288
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-58172- CVSS 4.0
- 9.3 Critical
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-288
- Updated
- 2026-11-02
OSV
Ocelot - IP Allow/Block List Bypass for WebSocket Upgrade Requests
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.
- Record
CVE-2026-58172- CVSS 4.0
- 9.3 Critical
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 - Weakness
- CWE-288
- Updated
- 2026-11-09
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| references | OSV | |
| references | CVE List | |
| facts | EUVD | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-58172 is a critical vulnerability (CVSS 9.3) in Threemammals Ocelot, published June 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.56%, the 47th percentile. No source names a fixed version.
References
github.com/ThreeMammals/Ocelot/issues/2403
vulncheck.com/advisories/ocelot-ip-allow-block-list-bypass-for-websocket-upgrade-requests
nvd.nist.gov/vuln/detail/CVE-2026-58172