# CVE-2026-118262: Echo: WebSocket proxy can retain connections and handlers after client disconnect


- **Severity:** High 8.2 (`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`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-118262, ECHO-ec06-f360-e7e1, GHSA-9969-6676-49h5, ROOT-APP-GOBINARY-GHSA-9969-6676-49h5, UBUNTU-CVE-2026-118262

## What is CVE-2026-118262?

CVE-2026-118262 is a high-severity vulnerability in labstack echo, published on 28 Oct 2026. 

### Official description

Echo 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.

Weakness: CWE-772 (Missing Release of Resource after Effective Lifetime)

## Which versions are affected by CVE-2026-118262?

4 open source packages ship an affected version, including github.com/labstack/echo/v4 and github.com/labstack/echo/v5.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/labstack/echo/v4` | Go | From 4.15.0 | 4.16.1 |
| `github.com/labstack/echo/v4` | Go | From 4.15.0 | 4.16.1 |
| `github.com/labstack/echo/v5` | Go | From 5.0.0 | 5.4.1 |
| `github.com/labstack/echo/v5` | Go | From 5.0.0 | 5.4.1 |

## How do I fix CVE-2026-118262?

Upgrade github.com/labstack/echo/v4 to 4.16.1 or later.

## Is CVE-2026-118262 being exploited?

There is no known exploitation of CVE-2026-118262 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-118262 and fix it if it is affected.

What it is: CVE-2026-118262 is a high-severity vulnerability in labstack echo, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-118262 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/labstack/echo/v4 (Go): affected from 4.15.0; fixed in 4.16.1
- github.com/labstack/echo/v4 (Go): affected from 4.15.0; fixed in 4.16.1
- github.com/labstack/echo/v5 (Go): affected from 5.0.0; fixed in 5.4.1
- github.com/labstack/echo/v5 (Go): affected from 5.0.0; fixed in 5.4.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-118262/ (Markdown: https://insights.sbomify.com/CVE-2026-118262/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-118262
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-118262
- OSV: https://osv.dev/vulnerability/CVE-2026-118262

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-118262/
Summaries are generated and may contain mistakes; the official description above is the record.