PSIRT Content-Encoding WAF Evasion

{
  "id": "e429bae89b612c530ed4983ae7b987c6085edb2de861598e22beee19152114f7",
  "url": "https://fortiguard.fortinet.com/psirt/FG-IR-26-157",
  "method": "llm",
  "payload": {
    "kind": "patch",
    "title": "PSIRT Content-Encoding WAF Evasion",
    "summary": "An incomplete list of disallowed inputs may let an unauthenticated attacker bypass FortiWeb WAF policies using crafted requests. Fortinet lists fixed upgrades for FortiWeb 8.0 and 7.6; older listed branches must migrate to a fixed release.",
    "evidence": "An incomplete list of disallowed inputs [CWE-184] in FortiWeb WAF may allow an unauthenticated attacker to bypass policies via specifically crafted requests.",
    "products": [
      {
        "name": {
          "value": "FortiWeb",
          "evidence": "FortiWeb 8.0"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "8.0.3 or above",
            "evidence": "Upgrade to 8.0.3 or above"
          }
        ],
        "affected_versions": [
          {
            "value": "8.0.0 through 8.0.2",
            "evidence": "8.0.0 through 8.0.2"
          }
        ]
      },
      {
        "name": {
          "value": "FortiWeb",
          "evidence": "FortiWeb 7.6"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.6.6 or above",
            "evidence": "Upgrade to 7.6.6 or above"
          }
        ],
        "affected_versions": [
          {
            "value": "7.6.0 through 7.6.5",
            "evidence": "7.6.0 through 7.6.5"
          }
        ]
      },
      {
        "name": {
          "value": "FortiWeb",
          "evidence": "FortiWeb 7.4"
        },
        "prerequisites": [
          {
            "value": "Migrate to a fixed release",
            "evidence": "Migrate to a fixed release"
          }
        ],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.4 all versions",
            "evidence": "7.4 all versions"
          }
        ]
      },
      {
        "name": {
          "value": "FortiWeb",
          "evidence": "FortiWeb 7.2"
        },
        "prerequisites": [
          {
            "value": "Migrate to a fixed release",
            "evidence": "Migrate to a fixed release"
          }
        ],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.2 all versions",
            "evidence": "7.2 all versions"
          }
        ]
      },
      {
        "name": {
          "value": "FortiWeb",
          "evidence": "FortiWeb 7.0"
        },
        "prerequisites": [
          {
            "value": "Migrate to a fixed release",
            "evidence": "Migrate to a fixed release"
          }
        ],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.0 all versions",
            "evidence": "7.0 all versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "fixed_cves": [],
    "related_cves": [
      {
        "value": "CVE-2026-70466",
        "evidence": "CVE ID CVE-2026-70466"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "Severity Medium"
  },
  "source_id": "official-fortinet-psirt",
  "document_id": 23575,
  "published_at": "2026-08-12T07:00:00+00:00"
}