FKIE_CVE-2026-39825

Vulnerability from fkie_nvd - Published: 2026-05-07 20:16 - Updated: 2026-06-17 10:42
Severity
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
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.
References
security@golang.orghttps://go.dev/cl/770541Patch
security@golang.orghttps://go.dev/issue/78948Issue Tracking
security@golang.orghttps://groups.google.com/g/golang-announce/c/qcCIEXso47MRelease Notes
security@golang.orghttps://pkg.go.dev/vuln/GO-2026-4976Vendor Advisory
Impacted products
Vendor Product Version
golang go *
golang go *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "net/http/httputil",
          "product": "net/http/httputil",
          "programRoutines": [
            {
              "name": "cleanQueryParams"
            },
            {
              "name": "ReverseProxy.ServeHTTP"
            }
          ],
          "vendor": "Go standard library",
          "versions": [
            {
              "lessThan": "1.25.10",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.26.3",
              "status": "affected",
              "version": "1.26.0-0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "security@golang.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "1C966EF3-C51C-4239-B5FC-C44A5202FEC8",
              "versionEndExcluding": "1.25.10",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "522E4CD0-2B99-4363-9C78-0BAFD988A2D6",
              "versionEndExcluding": "1.26.3",
              "versionStartIncluding": "1.26.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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\u0027s 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\u0026a2=x\u0026...\u0026a10000=x\u0026hidden=y\" can forward the parameter \"hidden=y\" while hiding it from the proxy\u0027s Rewrite function."
    }
  ],
  "id": "CVE-2026-39825",
  "lastModified": "2026-06-17T10:42:38.770",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-39825",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-08T16:46:43.329507Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-05-07T20:16:43.390",
  "references": [
    {
      "source": "security@golang.org",
      "tags": [
        "Patch"
      ],
      "url": "https://go.dev/cl/770541"
    },
    {
      "source": "security@golang.org",
      "tags": [
        "Issue Tracking"
      ],
      "url": "https://go.dev/issue/78948"
    },
    {
      "source": "security@golang.org",
      "tags": [
        "Release Notes"
      ],
      "url": "https://groups.google.com/g/golang-announce/c/qcCIEXso47M"
    },
    {
      "source": "security@golang.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://pkg.go.dev/vuln/GO-2026-4976"
    }
  ],
  "sourceIdentifier": "security@golang.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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