FKIE_CVE-2026-56858

Vulnerability from fkie_nvd - Published: 2026-08-13 22:17 - Updated: 2026-08-14 16:16
Severity
6.1 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Summary
Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.
References
security@golang.orghttps://go.dev/cl/807100
security@golang.orghttps://go.dev/issue/80435
security@golang.orghttps://groups.google.com/g/golang-announce/c/94pEornpRlI
security@golang.orghttps://pkg.go.dev/vuln/GO-2026-6091
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "html/template",
          "product": "html/template",
          "programRoutines": [
            {
              "name": "tJS"
            },
            {
              "name": "Template.Execute"
            },
            {
              "name": "Template.ExecuteTemplate"
            }
          ],
          "vendor": "Go standard library",
          "versions": [
            {
              "lessThan": "1.25.13",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.26.6",
              "status": "affected",
              "version": "1.26.0-0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.27.0-rc.3",
              "status": "affected",
              "version": "1.27.0-0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "security@golang.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Previously, pathological inputs could close an unescaped \u0027/\u0027 early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS."
    }
  ],
  "id": "CVE-2026-56858",
  "lastModified": "2026-08-14T16:16:57.367",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.1,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.7,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-56858",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-14T15:31:30.140536Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-13T22:17:22.207",
  "references": [
    {
      "source": "security@golang.org",
      "url": "https://go.dev/cl/807100"
    },
    {
      "source": "security@golang.org",
      "url": "https://go.dev/issue/80435"
    },
    {
      "source": "security@golang.org",
      "url": "https://groups.google.com/g/golang-announce/c/94pEornpRlI"
    },
    {
      "source": "security@golang.org",
      "url": "https://pkg.go.dev/vuln/GO-2026-6091"
    }
  ],
  "sourceIdentifier": "security@golang.org",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.