flaskBlog Stored XSS Vulnerability

{
  "id": "4a3a1243dcf1d5a3cff2a5d54cb9ac2a7e7d89caf3235409136202083f2f12c5",
  "url": "https://osv.dev/vulnerability/CVE-2025-55735",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "flaskBlog Stored XSS Vulnerability",
    "summary": "flaskBlog is a blog app built with Flask. In 2.8.0 and earlier, when creating a post, there's no validation of the content of the post stored in the variable \"postContent\". The vulnerability arises when displaying the content of the post using the | safe filter, that tells the engine to not escape the rendered content. This can lead to a stored XSS inside the content of the post. The code that causes the problem is in template/routes.html.",
    "evidence": "osv:CVE-2025-55735",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-55735",
      "aliases": [
        "CVE-2025-55735",
        "GHSA-gj9v-qhc3-gcfx"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/dogukanurker/flaskblog",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "7fea76d8c9ae624125ed86ed63e2c56dfad0d757"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.8.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "cpe": "cpe:2.3:a:dogukanurker:flaskblog:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.8.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.8.0",
            "2.7.0",
            "2.6.0",
            "2.5.0",
            "2.4.0",
            "2.3.0",
            "2.2.1",
            "2.2.0",
            "2.1.4",
            "2.1.3",
            "2.1.2",
            "2.1.1",
            "2.1.0",
            "2.0.12",
            "2.0.11",
            "2.0.10",
            "2.0.9",
            "2.0.8",
            "2.0.7",
            "2.0.6",
            "2.0.5",
            "2.0.4",
            "2.0.3",
            "2.0.2",
            "2.0.1",
            "2.0.0",
            "1.1.0",
            "1.0.9",
            "1.0.8",
            "1.0.7",
            "1.0.6",
            "1.0.5",
            "1.0.4",
            "1.0.3",
            "1.0.2",
            "1.0.1",
            "1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-55735.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.778878009Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/55xxx/CVE-2025-55735.json",
        "https://github.com/DogukanUrker/FlaskBlog/security/advisories/GHSA-gj9v-qhc3-gcfx",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-55735"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79",
          "CWE-807"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/55xxx/CVE-2025-55735.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-55735",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505197,
  "published_at": "2025-08-19T18:56:42.6+00:00"
}