# CVE-2026-118652: Echo: Reflected Cross-Site Scripting (XSS) via unsanitized JSONP callback in Context.JSONP / Context.JSONPBlob


- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-118652, ECHO-b997-6e99-fafb, GHSA-h9g5-28mm-hx3g, UBUNTU-CVE-2026-118652

## What is CVE-2026-118652?

CVE-2026-118652 is a medium-severity vulnerability in labstack echo, published on 28 Oct 2026. 

### Official description

Echo is a Go web framework. Prior to 4.16.0 and 5.4.0, Context.JSONP and Context.JSONPBlob concatenate an unvalidated callback value into a JavaScript response. A route that passes attacker-controlled input as the callback can return executable script syntax, allowing reflected cross-site scripting when a user loads the crafted response. The vulnerable jsonPBlob path performs no callback validation or escaping, and exploitation requires an application route that exposes attacker control over the callback argument. This issue is fixed in 4.16.0 and 5.4.0.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-118652?

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 | All versions | 4.16.0 |
| `github.com/labstack/echo/v4` | Go | All versions | 4.16.0 |
| `github.com/labstack/echo/v5` | Go | All versions | 5.4.0 |
| `github.com/labstack/echo/v5` | Go | All versions | 5.4.0 |

## How do I fix CVE-2026-118652?

Upgrade github.com/labstack/echo/v4 to 4.16.0 or later.

## Is CVE-2026-118652 being exploited?

There is no known exploitation of CVE-2026-118652 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-118652 and fix it if it is affected.

What it is: CVE-2026-118652 is a medium-severity vulnerability in labstack echo, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-118652 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/labstack/echo/v4 (Go): affected all versions; fixed in 4.16.0
- github.com/labstack/echo/v4 (Go): affected all versions; fixed in 4.16.0
- github.com/labstack/echo/v5 (Go): affected all versions; fixed in 5.4.0
- github.com/labstack/echo/v5 (Go): affected all versions; fixed in 5.4.0

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-2026-118652/ (Markdown: https://insights.sbomify.com/CVE-2026-118652/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-118652
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-118652
- OSV: https://osv.dev/vulnerability/CVE-2026-118652

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-118652/
Summaries are generated and may contain mistakes; the official description above is the record.