CVE-2026-39825 (GCVE-0-2026-39825)

Vulnerability from cvelistv5 – Published: 2026-05-07 19:41 – Updated: 2026-05-08 21:30
VLAI
Title
ReverseProxy forwards queries with more than urlmaxqueryparams parameters in net/http/httputil
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.
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-08 16:46 UTC
CWE
  • CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Assigner
References
Impacted products
Vendor Product Version CPE status
Go standard library net/http/httputil Affected: 0 , < 1.25.10 (semver)
Affected: 1.26.0-0 , < 1.26.3 (semver)
guessed Create a notification for this product.
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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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