FFmpeg Integer Narrowing Conversion OOB Memory Access in AV1 RTP Packetizer

{
  "id": "da6aa64de00711eead3a0f0d31731fcac2c653e1ce15c69c4cd8c1123dd71ff9",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-75145",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "FFmpeg Integer Narrowing Conversion OOB Memory Access in AV1 RTP Packetizer",
    "summary": "FFmpeg before commit b4c199c contains an incorrect integer narrowing conversion in the AV1 RTP packetizer (libavformat/rtpenc_av1.c). The OBU size is cast to long before comparison against the remaining frame size. On targets where long is 32 bits, including 64-bit Windows, sufficiently large OBU size values are sign-flipped by the narrowing cast, producing a negative value that passes the payload size check. This allows an oversized OBU to bypass the safety bound on affected platforms, leading to out-of-bounds memory access when the oversized value is subsequently used as a copy length.",
    "evidence": "cve:CVE-2026-75145",
    "products": [
      {
        "name": {
          "value": "FFmpeg",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-75145",
      "aliases": [
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      "metrics": [
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            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 5.8,
            "Automatable": "NOT_DEFINED",
            "attackVector": "LOCAL",
            "baseSeverity": "MEDIUM",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
            "exploitMaturity": "NOT_DEFINED",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "PASSIVE",
            "attackComplexity": "HIGH",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
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            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:H",
            "integrityImpact": "LOW",
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      "affected": [
        {
          "repo": "https://code.ffmpeg.org/FFmpeg/FFmpeg",
          "vendor": "FFmpeg",
          "product": "FFmpeg",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "b4c199c5906ff53368926c2a5839881f41957e7f",
              "versionType": "git"
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          "packageURL": "pkg:github/FFmpeg/FFmpeg",
          "defaultStatus": "unaffected"
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      ],
      "modified": "2026-10-27T10:14:32.244Z",
      "provider": "cve",
      "references": [
        "https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24090",
        "https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/b4c199c5906ff53368926c2a5839881f41957e7f",
        "https://www.vulncheck.com/advisories/ffmpeg-integer-narrowing-conversion-oob-memory-access-in-av1-rtp-packetizer"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-75145",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
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                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-08-21T19:52:00.435341Z"
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    "related_cves": [
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        "value": "CVE-2026-75145",
        "evidence": "/cveMetadata/cveId"
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    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 391796,
  "published_at": "2026-08-19T16:27:33.12+00:00"
}