FFmpeg Out-of-Bounds Read in DASH Demuxer via dashdec.c

{
  "id": "61c0fd372628bc86e55938a5c4f613f95216d1a420490ab811cc7fd5f35c2efd",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-75146",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "FFmpeg Out-of-Bounds Read in DASH Demuxer via dashdec.c",
    "summary": "FFmpeg before commit 65b0dab contains an out-of-bounds read in the DASH demuxer (libavformat/dashdec.c). When a live DASH manifest is refreshed with a startNumber that is lower than the previous value, the current sequence number is driven negative. The fragment retrieval function checked only the upper bound before indexing the fragments array, allowing a negative index to be used and causing an out-of-bounds read. A malicious or misconfigured DASH server can trigger this by serving a live manifest with a decreasing startNumber across a manifest refresh.",
    "evidence": "cve:CVE-2026-75146",
    "products": [
      {
        "name": {
          "value": "FFmpeg",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-75146",
      "aliases": [
        "CVE-2026-75146"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "Safety": "NOT_DEFINED",
            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 7.2,
            "Automatable": "NOT_DEFINED",
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N",
            "exploitMaturity": "NOT_DEFINED",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "PASSIVE",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
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          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
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        {
          "format": "CVSS",
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 8.1,
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
            "integrityImpact": "NONE",
            "userInteraction": "REQUIRED",
            "attackComplexity": "LOW",
            "availabilityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "HIGH"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
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      ],
      "affected": [
        {
          "repo": "https://code.ffmpeg.org/FFmpeg/FFmpeg",
          "vendor": "FFmpeg",
          "product": "FFmpeg",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "65b0dab903e5975e036b30ecc58f5935d4f151e0",
              "versionType": "git"
            }
          ],
          "packageURL": "pkg:github/FFmpeg/FFmpeg",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-27T10:14:32.933Z",
      "provider": "cve",
      "references": [
        "https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24093",
        "https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/65b0dab903e5975e036b30ecc58f5935d4f151e0",
        "https://www.vulncheck.com/advisories/ffmpeg-out-of-bounds-read-in-dash-demuxer-via-dashdec-c"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-75146",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-08-20T14:55:54.873673Z"
                  }
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            "providerMetadata": {
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              "dateUpdated": "2026-08-20T14:56:11.985Z"
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        "cna": {
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          "shortName": "VulnCheck",
          "dateUpdated": "2026-10-27T10:14:32.933Z"
        }
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    },
    "related_cves": [
      {
        "value": "CVE-2026-75146",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 391797,
  "published_at": "2026-08-19T16:28:19.356+00:00"
}