CVE-2026-39825

Public on

Last Modified: UTC

Moderate Moderate severity What does this mean?
6.5 CVSS v3 Score Breakdown

Description

A flaw was found in the net/http/httputil package, specifically within the ReverseProxy component. This vulnerability allows the ReverseProxy to forward query parameters that are not visible to Rewrite functions. This occurs because the ReverseProxy does not correctly consider the url.ParseQuery limit on the total number of query parameters. A remote attacker could exploit this to send hidden query parameters, potentially bypassing security policies or controls implemented by Rewrite functions, leading to information disclosure or unexpected behavior.

Statement

A flaw was found in Go's net/http/httputil package where ReverseProxy can forward query parameters that are hidden from Rewrite or Director functions. This occurs when the number of query parameters exceeds the url.ParseQuery limit (controlled by the GODEBUG setting urlmaxqueryparams). While Red Hat ships Go-based components across many products, exploitation requires that an application use ReverseProxy with a Rewrite or Director function that relies on query parameter inspection for security enforcement, which limits the practical impact of this vulnerability.

Mitigation

Increase the maximum number of query parameters allowed by setting the GODEBUG environment variable `urlmaxqueryparams` to a higher value (e.g., `GODEBUG=urlmaxqueryparams=20000`), or validate and enforce security controls on query parameters at the backend service rather than relying solely on the ReverseProxy's Rewrite or Director function for security filtering.

Additional information

External References

Affected Packages and Issued Red Hat Security Errata

Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.

Products / Services Components State Errata
Red Hat Enterprise Linux 10 golang Fixed RHSA-2026:22120
Red Hat Enterprise Linux 10.0 Extended Update Support golang Fixed RHSA-2026:49702
Red Hat Enterprise Linux 8 go-toolset:rhel8 Fixed RHSA-2026:22112
Red Hat Enterprise Linux 9 golang Fixed RHSA-2026:22121
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions golang Fixed This content is not included.RHSA-2026:61253
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions golang Fixed RHSA-2026:57649
Red Hat Enterprise Linux 9.6 Extended Update Support golang Fixed RHSA-2026:49712
multicluster engine for Kubernetes 2.11 multicluster-engine/backplane-rhel9-operator Fixed This content is not included.RHSA-2026:57194
multicluster engine for Kubernetes 2.11 multicluster-engine/hypershift-addon-rhel9-operator Fixed This content is not included.RHSA-2026:57194
multicluster engine for Kubernetes 2.11 multicluster-engine/work-rhel9 Fixed This content is not included.RHSA-2026:57194

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).

CVSS v3 Score Breakdown

Red Hat NVD cve.org
CVSS v3 Base Score 6.5 N/A 5.3
Attack Vector Network N/A Network
Attack Complexity Low N/A Low
Privileges Required None N/A None
User Interaction None N/A None
Scope Unchanged N/A Unchanged
Confidentiality Impact Low N/A Low
Integrity Impact Low N/A None
Availability Impact None N/A None

CVSS v3 Vector

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

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

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

 For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

 A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

 A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

 A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

 The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

 In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our This content is not included.Red Hat Vulnerability Scanner Certification program.

My product is listed as "Out of Support Scope". What does this mean?

 When a product is listed as "Out of Support Scope", it means a vulnerability with the impact level assigned to this CVE is no longer covered by its current support lifecycle phase. The product has been identified to contain the impacted component, but analysis to determine whether it is affected or not by this vulnerability was not performed. The product should be assumed to be affected. Customers are advised to apply any mitigation options documented on this page, consider removing or disabling the impacted component, or upgrade to a supported version of the product that has an update available.