Vulnerability-Lookup

GHSA-2VCC-5V34-9JC8

Vulnerability from github – Published: 2026-06-18 13:07 – Updated: 2026-06-18 13:07

Summary

TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes

Details

TinaCMS rich-text parsing and the default link/image renderers did not sanitize the url field on Slate link/image nodes. Content containing javascript: or data:text/html URLs — including case-variant, whitespace-padded, and control-character-obfuscated forms — is rendered into href/src and executes when the content is viewed. Any actor able to author rich-text content (for example a lower-privileged editor, or imported/external content) can achieve stored XSS against editors and site viewers.

Fixed in https://github.com/tinacms/tinacms/pull/7056 via a sanitizeUrl() helper (case-insensitive, whitespace/control-character-normalized scheme allow-list) applied recursively to Slate trees at parse time and in the default rich-text rendering.

Severity

4.8 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "tinacms"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.9.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@tinacms/mdx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55661"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79",
      "CWE-87"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-18T13:07:05Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "TinaCMS rich-text parsing and the default link/image renderers did not sanitize the `url` field on Slate link/image nodes. Content containing `javascript:` or `data:text/html` URLs \u2014 including case-variant, whitespace-padded, and control-character-obfuscated forms \u2014 is rendered into `href`/`src` and executes when the content is viewed. Any actor able to author rich-text content (for example a lower-privileged editor, or imported/external content) can achieve stored XSS against editors and site viewers.\n\nFixed in https://github.com/tinacms/tinacms/pull/7056 via a `sanitizeUrl()` helper (case-insensitive, whitespace/control-character-normalized scheme allow-list) applied recursively to Slate trees at parse time and in the default rich-text rendering.",
  "id": "GHSA-2vcc-5v34-9jc8",
  "modified": "2026-06-18T13:07:05Z",
  "published": "2026-06-18T13:07:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/tinacms/tinacms/security/advisories/GHSA-2vcc-5v34-9jc8"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tinacms/tinacms/pull/7056"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tinacms/tinacms"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes"
}

CVE-2026-55661 (GCVE-0-2026-55661)

Vulnerability from cvelistv5 – Published: 2026-07-01 20:44 – Updated: 2026-07-06 14:39

Title

TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes

Summary

Tina is a headless content management system. In versions prior to @tinacms/mdx 2.1.7 and tinacms 3.9.3, rich-text parsing and the default link/image renderers did not sanitize the url field on Slate link/image nodes. Content containing javascript: or data:text/html URLs — including case-variant, whitespace-padded, and control-character-obfuscated forms — is rendered into href/src and executes when the content is viewed. Any actor able to author rich-text content (for example a lower-privileged editor, or imported/external content) can achieve stored XSS against editors and site viewers. This issue is fixed in versions @tinacms/mdx 2.1.7 and tinacms 3.9.3.

Severity

4.8 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-06 14:39 UTC

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-87 - Improper Neutralization of Alternate XSS Syntax

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/tinacms/tinacms/security/advis…	x_refsource_CONFIRM
https://github.com/tinacms/tinacms/pull/7056	x_refsource_MISC

Impacted products

2 products

Vendor	Product	Version
tinacms	tinacms	Affected: < 3.9.3
tinacms	@tinacms/mdx	Affected: < 2.1.7

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55661",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-06T14:39:26.644011Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-06T14:39:33.214Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "tinacms",
          "vendor": "tinacms",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.9.3"
            }
          ]
        },
        {
          "product": "@tinacms/mdx",
          "vendor": "tinacms",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.1.7"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Tina is a headless content management system. In versions prior to @tinacms/mdx 2.1.7 and  tinacms 3.9.3,  rich-text parsing and the default link/image renderers did not sanitize the url field on Slate link/image nodes. Content containing javascript: or data:text/html URLs \u2014 including case-variant, whitespace-padded, and control-character-obfuscated forms \u2014 is rendered into href/src and executes when the content is viewed. Any actor able to author rich-text content (for example a lower-privileged editor, or imported/external content) can achieve stored XSS against editors and site viewers. This issue is fixed in versions @tinacms/mdx 2.1.7 and  tinacms 3.9.3."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 4.8,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "LOW",
            "subIntegrityImpact": "LOW",
            "userInteraction": "ACTIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-87",
              "description": "CWE-87: Improper Neutralization of Alternate XSS Syntax",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-01T20:44:50.116Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/tinacms/tinacms/security/advisories/GHSA-2vcc-5v34-9jc8",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/tinacms/tinacms/security/advisories/GHSA-2vcc-5v34-9jc8"
        },
        {
          "name": "https://github.com/tinacms/tinacms/pull/7056",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/tinacms/tinacms/pull/7056"
        }
      ],
      "source": {
        "advisory": "GHSA-2vcc-5v34-9jc8",
        "discovery": "UNKNOWN"
      },
      "title": "TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55661",
    "datePublished": "2026-07-01T20:44:50.116Z",
    "dateReserved": "2026-06-17T00:05:03.777Z",
    "dateUpdated": "2026-07-06T14:39:33.214Z",
    "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.

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.

Related by attack behaviour

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