CVE-2026-39825

Name: CVE-2026-39825
Creator: NVD / NIST
Published: 2026-05-07T20:16:43.39+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.39%

Last modified Jun 17, 2026

CVE-2026-39825 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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. EPSS estimates a 0.39% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

5.3/10

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

EPSS Probability

0.39%

30.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Golang	Go	< 1.25.10
Golang	Go	>= 1.26.0, < 1.26.3

References

https://go.dev/cl/770541Patch
https://go.dev/issue/78948Issue Tracking
https://groups.google.com/g/golang-announce/c/qcCIEXso47MRelease Notes
https://pkg.go.dev/vuln/GO-2026-4976Vendor Advisory

Timeline

Published: May 7, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-39825?

How severe is CVE-2026-39825?

CVE-2026-39825 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.39% probability of exploitation in the next 30 days.

How do I fix CVE-2026-39825?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-39825?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST