Input validation error in Go programming language - CVE-2026-39825
Published: July 31, 2026
Vulnerability identifier: #VU140616
CSH Severity: Medium
CVSS v4 BT: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2026-39825
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass proxy query parameter rewriting.
The vulnerability exists due to improper input validation in ReverseProxy.ServeHTTP in net/http/httputil when handling requests with excessive query parameters. A remote attacker can send a specially crafted request to bypass proxy query parameter rewriting.
The issue occurs when ReverseProxy is used with a Rewrite function, or a Director function that parses query parameters, and query parsing is subject to a total parameter limit.
Affected software
Go programming language
How to mitigate CVE-2026-39825
Install security update from vendor's website.
Go programming language - addressed in versions 1.25.10, 1.26.3