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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-118652
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-28 20:17:22 UTC
Updated2026-10-28 20:17:22 UTC
DescriptionEcho 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.

Risk And Classification

Primary CVSS: v3.1 6.1 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Problem Types: CWE-79 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
3.1CNADECLARED6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Labstack Echo affected < 4.16.0 Not specified
CNA Labstack Echo affected >= 5.0.0, < 5.4.0 Not specified

References

ReferenceSourceLinkTags
github.com/labstack/echo/security/advisories/GHSA-h9g5-28mm-hx3g [email protected] github.com
github.com/labstack/echo/releases/tag/v4.16.0 [email protected] github.com
github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af [email protected] github.com
github.com/labstack/echo/commit/b838391e2eade87ae7e5a09d7bb5087bec271ec1 [email protected] github.com
github.com/labstack/echo/releases/tag/v5.4.0 [email protected] github.com
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