Telegram-Stremio 5.1.0 Broken Object Authorization via Stream IDs

{
  "id": "11c6181326d191e9d5b3b2ada639ec32b25a211c5ea93ff8e9747bd4732fc02e",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-109427",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Telegram-Stremio 5.1.0 Broken Object Authorization via Stream IDs",
    "summary": "Telegram-Stremio through 5.1.0 contains a broken object-level authorization vulnerability that allows authenticated token holders to access arbitrary chat messages by forging unsigned, unauthenticated stream IDs decoded via encode_string/decode_string functions. Attackers can craft or enumerate sequential msg_id values and set a global flag in the stream_handler endpoint to route requests through the operator's personal Userbot account, exposing private channels, groups, and Saved Messages, while the unauthenticated thumb_handler endpoint further discloses thumbnails from those same chats without any token validation.",
    "evidence": "cve:CVE-2026-109427",
    "products": [
      {
        "name": {
          "value": "Telegram-Stremio",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
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    "severity": "high",
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      "id": "CVE-2026-109427",
      "aliases": [
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      "metrics": [
        {
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          "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",
            "exploitMaturity": "NOT_DEFINED",
            "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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            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
            "integrityImpact": "NONE",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "availabilityImpact": "NONE",
            "privilegesRequired": "LOW",
            "confidentialityImpact": "HIGH"
          },
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              "lang": "en",
              "value": "GENERAL"
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      "affected": [
        {
          "repo": "https://github.com/weebzone/Telegram-Stremio",
          "vendor": "weebzone",
          "product": "Telegram-Stremio",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "5.1.0"
            }
          ],
          "packageURL": "pkg:github/weebzone/Telegram-Stremio",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T20:33:54.245Z",
      "provider": "cve",
      "references": [
        "https://gist.github.com/mansurmavlankulov/489554cad7b38e07b9651c217f00fffb",
        "https://www.vulncheck.com/advisories/telegram-stremio-broken-object-authorization-via-stream-ids"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-109427",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
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                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T20:33:46.367536Z"
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          "shortName": "VulnCheck",
          "dateUpdated": "2026-10-12T20:35:49.858Z"
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    "related_cves": [
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        "value": "CVE-2026-109427",
        "evidence": "/cveMetadata/cveId"
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    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 341873,
  "published_at": "2026-10-12T20:35:49.858+00:00"
}