Vulnerability-Lookup

GHSA-Q4C4-6MQR-J8HQ

Vulnerability from github – Published: 2026-06-30 21:31 – Updated: 2026-06-30 21:31

Details

The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 5.8.0 via parser-derived 'avatar' and 'url' author metadata. This is due to insufficient input sanitization and output escaping on user-supplied MF2 author properties processed by the unauthenticated webmention REST endpoint and rendered directly into HTML 'value' attributes by the edit-comment-form template without esc_attr() or esc_url(). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a privileged user (moderator or administrator) opens the affected comment edit screen.

Severity

7.2 (High)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-10513"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-30T19:16:26Z",
    "severity": "HIGH"
  },
  "details": "The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 5.8.0 via parser-derived \u0027avatar\u0027 and \u0027url\u0027 author metadata. This is due to insufficient input sanitization and output escaping on user-supplied MF2 author properties processed by the unauthenticated webmention REST endpoint and rendered directly into HTML \u0027value\u0027 attributes by the edit-comment-form template without esc_attr() or esc_url(). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a privileged user (moderator or administrator) opens the affected comment edit screen.",
  "id": "GHSA-q4c4-6mqr-j8hq",
  "modified": "2026-06-30T21:31:43Z",
  "published": "2026-06-30T21:31:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-10513"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/webmention/tags/5.7.0/includes/handler/class-mf2.php#L129"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/webmention/tags/5.7.0/templates/edit-comment-form.php#L15"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/changeset/3583033/webmention"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/5a4e144a-3c84-4da3-8fa6-e5fe9c897efe?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-10513 (GCVE-0-2026-10513)

Vulnerability from cvelistv5 – Published: 2026-06-30 18:32 – Updated: 2026-07-01 10:32

Title

Webmention <= 5.8.0 - Unauthenticated Stored Cross-Site Scripting via MF2 'photo'/'url' Author Properties

Summary

Severity

7.2 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

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

Assigner

Wordfence

References

4 references

URL	Tags
https://www.wordfence.com/threat-intel/vulnerabil…
https://plugins.trac.wordpress.org/browser/webmen…
https://plugins.trac.wordpress.org/browser/webmen…
https://plugins.trac.wordpress.org/changeset/3583…

Impacted products

1 product

Vendor	Product	Version
pfefferle	Webmention	Affected: 0 , ≤ 5.8.0 (semver)

Credits

Volodymyr Kolesnykov

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-10513",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-01T10:28:37.750716Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
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        "providerMetadata": {
          "dateUpdated": "2026-07-01T10:32:06.942Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Webmention",
          "vendor": "pfefferle",
          "versions": [
            {
              "lessThanOrEqual": "5.8.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
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          "lang": "en",
          "type": "finder",
          "value": "Volodymyr Kolesnykov"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 5.8.0 via parser-derived \u0027avatar\u0027 and \u0027url\u0027 author metadata. This is due to insufficient input sanitization and output escaping on user-supplied MF2 author properties processed by the unauthenticated webmention REST endpoint and rendered directly into HTML \u0027value\u0027 attributes by the edit-comment-form template without esc_attr() or esc_url(). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a privileged user (moderator or administrator) opens the affected comment edit screen."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.2,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
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          "descriptions": [
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              "cweId": "CWE-79",
              "description": "CWE-79 Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
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        "orgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
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        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/webmention/tags/5.7.0/templates/edit-comment-form.php#L15"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/webmention/tags/5.7.0/includes/handler/class-mf2.php#L129"
        },
        {
          "url": "https://plugins.trac.wordpress.org/changeset/3583033/webmention"
        }
      ],
      "timeline": [
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          "time": "2026-06-01T05:07:45.000Z",
          "value": "Vendor Notified"
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          "lang": "en",
          "time": "2026-06-30T06:04:21.000Z",
          "value": "Disclosed"
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      ],
      "title": "Webmention \u003c= 5.8.0 - Unauthenticated Stored Cross-Site Scripting via MF2 \u0027photo\u0027/\u0027url\u0027 Author Properties"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
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    "datePublished": "2026-06-30T18:32:27.304Z",
    "dateReserved": "2026-06-01T04:52:29.224Z",
    "dateUpdated": "2026-07-01T10:32:06.942Z",
    "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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-Q4C4-6MQR-J8HQ

CVE-2026-10513 (GCVE-0-2026-10513)

Tags

Sightings

Nomenclature