Echo: WebSocket proxy can retain connections and handlers after client disconnect

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-118262
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-28 19:17:30 UTC
Updated2026-10-28 19:17:30 UTC
DescriptionEcho is a Go web framework. From 4.15.0 until 4.16.1 and 5.4.1, Echo's Proxy middleware can retain a handler, copy goroutines, and network connections after a WebSocket client disconnects when the upstream keeps its connection open. The raw proxy waits for both copy directions without reliably closing the peer connection when one direction ends, including when a rejected upgrade response uses HTTP keep-alive. Repeated connections can accumulate resources and cause denial of service, depending on proxy-route accessibility, upstream behavior, and connection deadlines. This issue is fixed in 4.16.1 and 5.4.1.

Risk And Classification

Primary CVSS: v4.0 8.2 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/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

Problem Types: CWE-772 | CWE-772 CWE-772: Missing Release of Resource after Effective Lifetime

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.2HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED8.2HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Labstack Echo affected >= 4.15.0, < 4.16.1 Not specified
CNA Labstack Echo affected >= 5.0.0, < 5.4.1 Not specified

References

ReferenceSourceLinkTags
github.com/labstack/echo/security/advisories/GHSA-9969-6676-49h5 [email protected] github.com
github.com/labstack/echo/releases/tag/v4.16.1 [email protected] github.com
github.com/labstack/echo/releases/tag/v5.4.1 [email protected] github.com
github.com/labstack/echo/commit/3fb0ba7e17645bb65611e2a08875d0a2f65c421f [email protected] github.com
github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec [email protected] github.com
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