Vulnerability · Published Oct 28, 2026 · Assigned by GitHub_M
CVE-2026-118652Echo: Reflected Cross-Site Scripting (XSS) via unsanitized JSONP callback in Context.JSONP / Context.JSONPBlob
Medium 6.1
In plain English
A medium-severity cross-site scripting in echo from labstack. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | golang-github-labstack-echo | no fix listed | DEBIAN-CVE-2026-118652 |
| Debian:13 | golang-github-labstack-echo | no fix listed | DEBIAN-CVE-2026-118652 |
| Debian:14 | golang-github-labstack-echo | no fix listed | DEBIAN-CVE-2026-118652 |
| Go | github.com/labstack/echo/v4 | 4.16.0 | GO-2026-6876 |
| Go | github.com/labstack/echo/v4 | 4.16.0 | GHSA-h9g5-28mm-hx3g |
| Go | github.com/labstack/echo/v5 | 5.4.0 | GHSA-h9g5-28mm-hx3g |
| Go | github.com/labstack/echo/v5 | 5.4.0 | GO-2026-6876 |
| Ubuntu:22.04:LTS | golang-github-labstack-echo | no fix listed | UBUNTU-CVE-2026-118652 |
| Ubuntu:24.04:LTS | golang-github-labstack-echo | no fix listed | UBUNTU-CVE-2026-118652 |
| Ubuntu:26.04:LTS | golang-github-labstack-echo | no fix listed | UBUNTU-CVE-2026-118652 |
| Ubuntu:26.10 | golang-github-labstack-echo | no fix listed | UBUNTU-CVE-2026-118652 |
| Ubuntu:22.04:LTS | golang-github-labstack-echo.v2 | no fix listed | UBUNTU-CVE-2026-118652 |
| Ubuntu:22.04:LTS | golang-github-labstack-echo.v3 | no fix listed | UBUNTU-CVE-2026-118652 |
Affected products (as reported)
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
- https://github.com/labstack/echo/security/advisories/GHSA-h9g5-28mm-hx3g x_refsource_CONFIRM
- https://github.com/labstack/echo/commit/b838391e2eade87ae7e5a09d7bb5087bec271ec1 x_refsource_MISC
- https://github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af x_refsource_MISC
- https://github.com/labstack/echo/releases/tag/v4.16.0 x_refsource_MISC
- https://github.com/labstack/echo/releases/tag/v5.4.0 x_refsource_MISC