Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-05-11 05:44

Modified

2026-09-08 08:34

Summary

Bypass of meta content URL escaping causes XSS in html/template

Details

CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a tag's attribute. If the URL content were to insert ASCII whitespaces around the '=' rune inside of the attribute, the escaper would fail to similarly escape it, leading to XSS.

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "golang",
        "purl": "pkg:bitnami/golang"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.25.10"
            },
            {
              "introduced": "1.26.0-0"
            },
            {
              "fixed": "1.26.3"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-39823"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a \u003cmeta\u003e tag\u0027s \u003ccontent\u003e attribute. If the URL content were to insert ASCII whitespaces around the \u0027=\u0027 rune inside of the \u003ccontent\u003e attribute, the escaper would fail to similarly escape it, leading to XSS.",
  "id": "BIT-golang-2026-39823",
  "modified": "2026-09-08T08:34:36.952Z",
  "published": "2026-05-11T05:44:33.709Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://go.dev/cl/769920"
    },
    {
      "type": "REPORT",
      "url": "https://go.dev/issue/78913"
    },
    {
      "type": "ARTICLE",
      "url": "https://groups.google.com/g/golang-announce/c/qcCIEXso47M"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39823"
    },
    {
      "type": "ADVISORY",
      "url": "https://pkg.go.dev/vuln/GO-2026-4982"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Bypass of meta content URL escaping causes XSS in html/template"
}

CVE-2026-39823 (GCVE-0-2026-39823)

Vulnerability from cvelistv5 – Published: 2026-05-07 19:41 – Updated: 2026-05-08 14:05

Title

Bypass of meta content URL escaping causes XSS in html/template

Summary

CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a <meta> tag's <content> attribute. If the URL content were to insert ASCII whitespaces around the '=' rune inside of the <content> attribute, the escaper would fail to similarly escape it, leading to XSS.

Severity

6.1 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-08 14:05 UTC

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

Go Google root

References

4 references

URL	Tags
https://go.dev/issue/78913
https://go.dev/cl/769920
https://groups.google.com/g/golang-announce/c/qcC…
https://pkg.go.dev/vuln/GO-2026-4982

Impacted products

1 product

Vendor	Product	Version
Go standard library	html/template	Affected: 0 , < 1.25.10 (semver) Affected: 1.26.0-0 , < 1.26.3 (semver)

Credits

Samy Ghannad

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-39823",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-08T14:05:34.310805Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-08T14:05:55.152Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "html/template",
          "product": "html/template",
          "programRoutines": [
            {
              "name": "tMetaContent"
            },
            {
              "name": "Template.Execute"
            },
            {
              "name": "Template.ExecuteTemplate"
            }
          ],
          "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"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Samy Ghannad"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a \u003cmeta\u003e tag\u0027s \u003ccontent\u003e attribute. If the URL content were to insert ASCII whitespaces around the \u0027=\u0027 rune inside of the \u003ccontent\u003e attribute, the escaper would fail to similarly escape it, leading to XSS."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-07T19:41:19.524Z",
        "orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
        "shortName": "Go"
      },
      "references": [
        {
          "url": "https://go.dev/issue/78913"
        },
        {
          "url": "https://go.dev/cl/769920"
        },
        {
          "url": "https://groups.google.com/g/golang-announce/c/qcCIEXso47M"
        },
        {
          "url": "https://pkg.go.dev/vuln/GO-2026-4982"
        }
      ],
      "title": "Bypass of meta content URL escaping causes XSS in html/template"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
    "assignerShortName": "Go",
    "cveId": "CVE-2026-39823",
    "datePublished": "2026-05-07T19:41:19.524Z",
    "dateReserved": "2026-04-07T18:13:03.527Z",
    "dateUpdated": "2026-05-08T14:05:55.152Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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Vulnerability from bitnami_vulndb

CVE-2026-39823 (GCVE-0-2026-39823)

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