Echo is a Go web framework
labstack · echo
The Proxy middleware in the Echo Go web framework (labstack/echo) selects a raw tunnel from a client WebSocket upgrade request before confirming that the configured upstream accepted the upgrade. An attacker with access to an accessible proxy route can, when the upstream rejects the upgrade with an ordinary keep-alive response, have later HTTP requests on that connection sent directly to the upstream, bypassing Echo's router and route-specific middleware, provided the target lacks independent upstream authorization.
Echo is a Go web framework. From 4.0.0 until 4.16.1 and 5.4.1, Echo's Proxy middleware selects a raw tunnel from a client WebSocket upgrade request before verifying that the configured upstream accepted the upgrade. If the upstream rejects the upgrade with an ordinary keep-alive response, later HTTP requests on the connection are sent directly to that upstream without passing through Echo's router or route-specific middleware. This can bypass authentication or authorization enforced only by Echo routes, but requires an accessible proxy route, a cooperating rejected-upgrade response, and a target without independent upstream authorization. This issue is fixed in 4.16.1 and 5.4.1.
- Exploited
- Not confirmed
- Reports
- 0
- Tactics
- 0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
Disclosed on 28 Oct 2026. No public exploit code or confirmed exploitation is recorded.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linkedNo ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.
Am I affected? What do I upgrade to?
From GitHub Security Advisories and OSV2 packages in 1 ecosystem. No single main package: each of these ships the affected code.
- Gogithub.com/labstack/echo/v4Affected: 4.0.0 up to 4.16.1Upgrade to 4.16.1 or later
- Gogithub.com/labstack/echo/v5Affected: 5.0.0 up to 5.4.1Upgrade to 5.4.1 or later
What security researchers reported
Not named in any threat report yetAlso mentioned in 2 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Known_Cve | Oct 31, 2026 | Part 2/330 Oct 2026
- Known_Cve | Oct 30, 2026 | Part 2/229 Oct 2026