{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "last_affected": "8.1.2"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "38b88335f99e76ed89ff3c93f877fdefce736c13"
            }
          ],
          "repo": "https://github.com/ffmpeg/ffmpeg",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-908"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66038.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "last_affected": "8.1.2"
          }
        ],
        "source": "AFFECTED_FIELD"
      },
      {
        "extracted_events": [
          {
            "last_affected": "8.1.2"
          }
        ],
        "source": "CPE_FIELD"
      },
      {
        "extracted_events": [
          {
            "fixed": "8.1.2"
          }
        ],
        "source": "DESCRIPTION"
      }
    ]
  },
  "details": "FFmpeg through 8.1.2, fixed in commit 8670835, contains an information disclosure vulnerability in the LCL/ZLIB video decoder that allows attackers to expose uninitialized heap memory by supplying a valid zlib stream that inflates to fewer bytes than the expected frame size. The zlib_decomp() function in lcldec.c treats short decompression as non-fatal and continues to the RGB24 conversion path, which copies a full frame's worth of rows from the allocation buffer using original frame dimensions, causing uninitialized heap contents including pointer-derived allocator bytes to be copied into the attacker-observable AVFrame output and potentially defeating ASLR in long-lived media processing services.",
  "id": "CVE-2026-66038",
  "modified": "2026-08-12T03:51:20.242157495Z",
  "published": "2026-07-24T19:39:27.448Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://code.ffmpeg.org/FFmpeg/FFmpeg"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66038.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66038"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/ffmpeg-lcl-zlib-video-decoder-information-disclosure-via-lcldec-c"
    },
    {
      "type": "REPORT",
      "url": "https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23626"
    },
    {
      "type": "FIX",
      "url": "https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/e7cbfd1c507b57a806a5825b87d609963e862c8c"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FFmpeg LCL/ZLIB Video Decoder Information Disclosure via lcldec.c"
}