MISP Guard Case-Sensitive Policy Bypass Allows Unauthorized Feed Data Forwarding

{
  "id": "8544cd971ab518d6a7b9f7306eaab73618f90e077f2467460c68d034d0263d9b",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-116469",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MISP Guard Case-Sensitive Policy Bypass Allows Unauthorized Feed Data Forwarding",
    "summary": "MISP Guard, a proxy-based security filter for MISP feed distribution, contains a case-sensitivity flaw in multiple policy enforcement checks. The functions check_required_taxonomy_exists, check_required_taxonomy_tags_allowed, check_blocked_attribute_categories, and check_blocked_analyst_data_sharing_groups_uuids performed case-sensitive string comparisons when matching event tags, attribute categories, and sharing-group UUIDs against configured allow/block lists. An attacker with the ability to create or modify events in a MISP instance (or a connected instance that pushes events through the guard) could craft events using different letter case in taxonomy tag names, attribute categories, or sharing-group UUIDs to bypass the configured security policies. For example, if the policy requires the 'tlp' taxonomy with only 'tlp:clear' allowed, an event tagged 'TLP:AMBER' would not be recognized as belonging to the 'tlp' taxonomy and would therefore not be checked against the allowed-tags list, resulting in the event being forwarded to feed consumers. Similarly, a blocked attribute category such as 'Person' would not match a configured block entry of 'person', allowing the attribute to pass through the filter. The security impact is unauthorized disclosure of threat-intelligence data that the operator intended to restrict. Events carrying non-allowed TLP (Traffic Light Protocol) markings, blocked attribute categories, or blocked sharing-group associations are forwarded to downstrea",
    "evidence": "cve:CVE-2026-116469",
    "products": [
      {
        "name": {
          "value": "misp-guard",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-116469",
      "aliases": [
        "CVE-2026-116469"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "Safety": "NOT_DEFINED",
            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 7.1,
            "Automatable": "NOT_DEFINED",
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "privilegesRequired": "LOW",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
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              "value": "GENERAL"
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          "other": {
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                {
                  "Automatable": "yes"
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                  "Technical Impact": "partial"
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              "version": "2.0.3",
              "timestamp": "2026-10-26T10:33:59Z"
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      "affected": [
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          "cpes": [
            "cpe:2.3:a:misp:misp-guard:*:*:*:*:*:*:*:*"
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          "repo": "https://github.com/MISP/misp-guard",
          "vendor": "MISP",
          "modules": [
            "src/mispguard.py"
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          "product": "misp-guard",
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              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "1.3"
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          "programFiles": [
            "src/mispguard.py"
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          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-27T18:14:58.333Z",
      "provider": "cve",
      "references": [
        "https://github.com/MISP/misp-guard/commit/9868b1d93fc9cc40cc7c69ca11c86afd825bbc1c"
      ],
      "provider_metadata": {
        "adp": [
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            "title": "CISA ADP Vulnrichment",
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                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-116469",
                    "role": "CISA Coordinator",
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                        "Automatable": "no"
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                    "version": "2.0.3",
                    "timestamp": "2026-10-26T13:32:47.760705Z"
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    "related_cves": [
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        "value": "CVE-2026-116469",
        "evidence": "/cveMetadata/cveId"
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    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 397817,
  "published_at": "2026-10-26T10:35:51.992+00:00"
}