CVE-2026-39825

5.3 MEDIUM
Published: May 07, 2026 Modified: May 13, 2026
View on NVD

Description

ReverseProxy can forward queries containing parameters not visible to Rewrite functions. When used with a Rewrite function, or a Director function which parses query parameters, ReverseProxy sanitizes the forwarded request to remove query parameters which are not parsed by url.ParseQuery. ReverseProxy does not take ParseQuery's limit on the total number of query parameters (controlled by GODEBUG=urlmaxqueryparams=N) into account. This can permit ReverseProxy to forward a request containing a query parameter that is not visible to the Rewrite function. For example, the query "a1=x&a2=x&...&a10000=x&hidden=y" can forward the parameter "hidden=y" while hiding it from the proxy's Rewrite function.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://go.dev/cl/770541
Source: security@golang.org
Patch
https://go.dev/issue/78948
Source: security@golang.org
Issue Tracking
https://groups.google.com/g/golang-announce/c/qcCIEXso47M
Source: security@golang.org
Release Notes
https://pkg.go.dev/vuln/GO-2026-4976
Source: security@golang.org
Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.3 / 10.0
EPSS (Exploit Probability)
0.4%
31th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

golang