CVE-2026-118652
Echo: Reflected Cross-Site Scripting (XSS) via unsanitized JSONP callback in Context.JSONP / Context.JSONPBlob
CVSS Score
6.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-79 |
| Vendor | labstack |
| Product | echo |
| Published | Oct 28, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
labstack / echo
< 4.16.0 >= 5.0.0, < 5.4.0
References
github.com: https://github.com/labstack/echo/security/advisories/GHSA-h9g5-28mm-hx3g github.com: https://github.com/labstack/echo/commit/b838391e2eade87ae7e5a09d7bb5087bec271ec1 github.com: https://github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af github.com: https://github.com/labstack/echo/releases/tag/v4.16.0 github.com: https://github.com/labstack/echo/releases/tag/v5.4.0