Flask 3.1.3 security fix release

{
  "id": "940494484d55cbea235010378a4532ae27b98ba466b5b2fd76526ddc0e44903c",
  "url": "https://github.com/pallets/flask/releases/tag/3.1.3",
  "method": "llm",
  "payload": {
    "kind": "patch",
    "title": "Flask 3.1.3 security fix release",
    "summary": "Flask 3.1.3 fixes a security issue: session access is marked for key-only operations such as `in` and `len`.",
    "evidence": "This is the Flask 3.1.3 security fix release, which fixes a security issue",
    "products": [
      {
        "name": {
          "value": "Flask",
          "evidence": "Flask 3.1.3 security fix release"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.1.3",
            "evidence": "Flask 3.1.3 security fix release"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "fixed_cves": [],
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "github-pallets-flask",
  "document_id": 22089,
  "published_at": "2026-02-19T05:01:30+00:00"
}