CVE-2026-39825

ADVISORY - golang

Summary

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.

Common Weakness Enumeration (CWE)


GoLang

CREATED

UPDATED

ADVISORY IDGO-2026-4976
EXPLOITABILITY SCORE

-

EXPLOITS FOUND
-
COMMON WEAKNESS ENUMERATION (CWE)-
RATING UNAVAILABLE FROM ADVISORY
PackageTypeOS NameOS VersionAffected RangesFix Versions
stdlibgolang-->=1.26.0-0,<1.26.31.26.3
stdlibgolang--<1.25.101.25.10

Severity and metrics

No CVSS data available from this advisory.